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Table of Contents

Name

orterun, mpirun, mpiexec - Execute serial and paralleljobs in Open MPI. oshrun, shmemrun - Execute serial and parallel jobs inOpen SHMEM.Hw-module

Note:mpirun, mpiexec, and orterun are all synonyms for eachother as well as oshrun, shmemrun in case Open SHMEM is installed. Usingany of the names will produce the same behavior.

Synopsis

Single ProcessMultiple Data (SPMD) Model:

mpirun [ options ] <program> [ <args> ]

MultipleInstruction Multiple Data (MIMD) Model:

mpirun [ global_options ] [ local_options1 ]
<program1> [ <args1> ] : [ local_options2 ]
<program2> [ <args2> ] : ... :
[ local_optionsN ]
<programN> [ <argsN> ]

Note that in both models, invoking mpirun via an absolutepath name is equivalent to specifying the --prefix option with a <dir> valueequivalent to the directory where mpirun resides, minus its last subdirectory. For example:

% /usr/local/bin/mpirun ...

is equivalent to

% mpirun --prefix /usr/local

Quick Summary

If you are simply looking for how to run an MPI application,you probably want to use a command line of the following form:

% mpirun[ -np X ] [ --hostfile <filename> ] <program>

This will run X copies of <program> in your current run-time environment(if running under a supported resource manager, Open MPI’s mpirun will usuallyautomatically use the corresponding resource manager process starter, asopposed to, for example, rsh or ssh, which require the use of a hostfile,or will default to running all X copies on the localhost), scheduling (bydefault) in a round-robin fashion by CPU slot. See the rest of this pagefor more details.

Please note that mpirun automatically binds processesas of the start of the v1.8 series. Three binding patterns are used in theabsence of any further directives:

Bind to core:
when the number of processesis <= 2
Bind to socket:
when the number of processes is > 2
Bind to none:
when oversubscribed

If your application uses threads, then you probablywant to ensure that you are either not bound at all (by specifying --bind-tonone), or bound to multiple cores using an appropriate binding level orspecific number of processing elements per application process.

Options

mpirun will send the name of the directory where it was invoked on thelocal node to each of the remote nodes, and attempt to change to that directory. See the 'Current Working Directory' section below for further details.
<program>
The program executable. This is identified as the first non-recognizedargument to mpirun.
<args>
Pass these run-time arguments to every new process. These must always be the last arguments to mpirun. If an app context fileis used, <args> will be ignored.
-h, --help
Display help for this command
-q, --quiet
Suppress informative messages from orterun during applicationexecution.
-v, --verbose
Be verbose
-V, --version
Print version number. Ifno other arguments are given, this will also cause orterun to exit.
-N<num>

Launch num processes per node on all allocated nodes (synonym for npernode).
-display-map, --display-map
Display a table showing the mapped location ofeach process prior to launch.
-display-allocation, --display-allocation
Displaythe detected resource allocation.
-output-proctable, --output-proctable
Outputthe debugger proctable after launch.
-dvm, --dvm
Create a persistent distributedvirtual machine (DVM).
-max-vm-size, --max-vm-size <size>
Number of processesto run.
-novm, --novm
Execute without creating an allocation-spanning virtualmachine (only start daemons on nodes hosting application procs).
-hnp,--hnp <arg0>
Specify the URI of the Head Node Process (HNP), or the name ofthe file (specified as file:filename) that contains that info.

Use oneof the following options to specify which hosts (nodes) of the clusterto run on. Note that as of the start of the v1.8 release, mpirun will launcha daemon onto each host in the allocation (as modified by the followingoptions) at the very beginning of execution, regardless of whether or notapplication processes will eventually be mapped to execute there. This isdone to allow collection of hardware topology information from the remotenodes, thus allowing us to map processes against known topology. However,it is a change from the behavior in prior releases where daemons were onlylaunched after mapping was complete, and thus only occurred on nodes whereapplication processes would actually be executing.

-H, -host, --host <host1,host2,...,hostN>
List of hosts on which to invoke processes.
-hostfile, --hostfile <hostfile>
Provide a hostfile to use.
-default-hostfile, --default-hostfile <hostfile>
Provide a default hostfile.
-machinefile, --machinefile <machinefile>
Synonymfor -hostfile.
-cpu-set, --cpu-set <list>
Restrict launched processes to thespecified logical cpus on each node (comma-separated list). Note that thebinding options will still apply within the specified envelope - e.g., youcan elect to bind each process to only one cpu within the specified cpuset.

The following options specify the number of processes to launch.Note that none of the options imply a particular binding policy - e.g., requestingN processes for each socket does not imply that the processes will be boundto the socket.

-c, -n, --n, -np <#>
Run this many copies of the program on thegiven nodes. This option indicates that the specified file is an executableprogram and not an application context. If no value is provided for thenumber of copies to execute (i.e., neither the '-np' nor its synonyms areprovided on the command line), Open MPI will automatically execute a copyof the program on each process slot (see below for description of a 'processslot'). This feature, however, can only be used in the SPMD model and willreturn an error (without beginning execution of the application) otherwise. -<>
  • Launch N times the number of objects of the specified type on each node.
    • -npersocket, --npersocket <#persocket>
    On each node, launch this many processestimes the number of processor sockets on the node. The -npersocket optionalso turns on the -bind-to-socket option. (deprecated in favor of --map-by ppr:n:socket)
    -npernode, --npernode <#pernode>
    On each node, launch this many processes.(deprecated in favor of --map-by ppr:n:node)
    -pernode, --pernode
    On each node,launch one process -- equivalent to -npernode 1. (deprecated in favor of --map-byppr:1:node)

    To map processes:

    --map-by <foo>
    Map to the specified object,defaults to socket. Supported options include slot, hwthread, core, L1cache,L2cache, L3cache, socket, numa, board, node, sequential, distance, andppr. Any object can include modifiers by adding a : and any combinationof PE=n (bind n processing elements to each proc), SPAN (load balance theprocesses across the allocation), OVERSUBSCRIBE (allow more processes ona node than processing elements), and NOOVERSUBSCRIBE. This includes PPR,where the pattern would be terminated by another colon to separate it fromthe modifiers.
    -bycore, --bycore
    Map processes by core (deprecated in favorof --map-by core)
    -byslot, --byslot
    Map and rank processes round-robin by slot.
    -nolocal, --nolocal
    Do not run any copies of the launched application onthe same node as orterun is running. This option will override listingthe localhost with --host or any other host-specifying mechanism.
    -nooversubscribe,--nooversubscribe
    Do not oversubscribe any nodes; error (without startingany processes) if the requested number of processes would cause oversubscription.This option implicitly sets 'max_slots' equal to the 'slots' value foreach node. (Enabled by default).
    -oversubscribe, --oversubscribe
    Nodes areallowed to be oversubscribed, even on a managed system, and overloadingof processing elements.
    -bynode, --bynode
    Launch processes one per node, cyclingby node in a round-robin fashion. This spreads processes evenly among nodesand assigns MPI_COMM_WORLD ranks in a round-robin, 'by node' manner.
    -cpu-list,--cpu-list <cpus>
    List of processor IDs to bind processes to [default=NULL].

    To order processes’ ranks in MPI_COMM_WORLD:

    --rank-by <foo>
    Rank in round-robinfashion according to the specified object, defaults to slot. Supported optionsinclude slot, hwthread, core, L1cache, L2cache, L3cache, socket, numa,board, and node.

    For process binding:

    --bind-to <foo>
    Bind processes tothe specified object, defaults to core. Supported options include slot,hwthread, core, l1cache, l2cache, l3cache, socket, numa, board, and none.
    -cpus-per-proc, --cpus-per-proc <#perproc>
    Bind each process to the specified numberof cpus. (deprecated in favor of --map-by <obj>:PE=n)
    -cpus-per-rank, --cpus-per-rank<#perrank>
    Alias for -cpus-per-proc. (deprecated in favor of --map-by <obj>:PE=n)
    -bind-to-core, --bind-to-core
    Bind processes to cores (deprecated in favor of--bind-to core)
    -bind-to-socket, --bind-to-socket
    Bind processes to processor sockets (deprecated in favor of --bind-to socket)
    -report-bindings, --report-bindings
    Report any bindings for launched processes.

    For rankfiles:

    -rf, --rankfile<rankfile>
    Provide a rankfile file.

    To manage standard I/O:

    -output-filename,--output-filename <filename>
    Redirect the stdout, stderr, and stddiag of allprocesses to a process-unique version of the specified filename. Any directoriesin the filename will automatically be created. Each output file will consistof filename.id, where the id will be the processes’ rank in MPI_COMM_WORLD,left-filled with zero’s for correct ordering in listings. A relative pathvalue will be converted to an absolute path based on the cwd where mpirunis executed. Note that this will not work on environments where the filesystem on compute nodes differs from that where mpirun is executed.
    -stdin,--stdin <rank>
    The MPI_COMM_WORLD rank of the process that is to receive stdin.The default is to forward stdin to MPI_COMM_WORLD rank 0, but this optioncan be used to forward stdin to any process. It is also acceptable to specifynone, indicating that no processes are to receive stdin.
    -merge-stderr-to-stdout,--merge-stderr-to-stdout
    Merge stderr to stdout for each process.
    -tag-output,--tag-output
    Tag each line of output to stdout, stderr, and stddiag with [jobid,MCW_rank]<stdxxx> indicating the process jobid and MPI_COMM_WORLD rank ofthe process that generated the output, and the channel which generatedit.
    -timestamp-output, --timestamp-output
    Timestamp each line of output tostdout, stderr, and stddiag.
    -xml, --xml
    Provide all output to stdout, stderr,and stddiag in an xml format.
    -xml-file, --xml-file <filename>
    Provide all outputin XML format to the specified file.
    -xterm, --xterm <ranks>
    Display the outputfrom the processes identified by their MPI_COMM_WORLD ranks in separatexterm windows. The ranks are specified as a comma-separated list of ranges,with a -1 indicating all. A separate window will be created for each specifiedprocess. Note: xterm will normally terminate the window upon terminationof the process running within it. However, by adding a '!' to the end ofthe list of specified ranks, the proper options will be provided to ensurethat xterm keeps the window open after the process terminates, thus allowingyou to see the process’ output. Each xterm window will subsequently needto be manually closed. Note: In some environments, xterm may require thatthe executable be in the user’s path, or be specified in absolute or relativeterms. Thus, it may be necessary to specify a local executable as './foo'instead of just 'foo'. If xterm fails to find the executable, mpirun willhang, but still respond correctly to a ctrl-c. If this happens, please checkthat the executable is being specified correctly and try again.

    To managefiles and runtime environment:

    -path, --path <path>
    <path> that will be usedwhen attempting to locate the requested executables. This is used priorto using the local PATH setting.
    --prefix <dir>
    Prefix directory that willbe used to set the PATH and LD_LIBRARY_PATH on the remote node before invokingOpen MPI or the target process. See the 'Remote Execution' section, below.
    --noprefix
    Disable the automatic --prefix behavior
    -s, --preload-binary
    Copythe specified executable(s) to remote machines prior to starting remoteprocesses. The executables will be copied to the Open MPI session directoryand will be deleted upon completion of the job.
    --preload-files <files>
    Preloadthe comma separated list of files to the current working directory of theremote machines where processes will be launched prior to starting thoseprocesses.
    -set-cwd-to-session-dir, --set-cwd-to-session-dir
    Set the working directoryof the started processes to their session directory.
    -wd <dir>
    Synonym for-wdir.
    -wdir <dir>
    Change to the directory <dir> before the user’s program executes.See the 'Current Working Directory' section for notes on relative paths.Note: If the -wdir option appears both on the command line and in an applicationcontext, the context will take precedence over the command line. Thus, ifthe path to the desired wdir is different on the backend nodes, then itmust be specified as an absolute path that is correct for the backend node.
    -x <env>
    Export the specified environment variables to the remote nodesbefore executing the program. Only one environment variable can be specifiedper -x option. Existing environment variables can be specified or new variablenames specified with corresponding values. For example: % mpirun -xDISPLAY -x OFILE=/tmp/out ...

    The parser for the -x option is not very sophisticated; it does not evenunderstand quoted values. Users are advised to set variables in the environment,and then use -x to export (not define) them.

    Setting MCA parameters:

    -gmca, --gmca <key> <value>
    Pass global MCA parameters that are applicable toall contexts. <key> is the parameter name; <value> is the parameter value.
    -mca, --mca <key> <value>
    Send arguments to various MCA modules. See the 'MCA'section, below.
    -am <arg0>
    Aggregate MCA parameter set file list.
    -tune,--tune <tune_file>
    Specify a tune file to set arguments for various MCA modulesand environment variables. See the 'Setting MCA parameters and environmentvariables from file' section, below.

    For debugging:

    -debug, --debug
    Invokethe user-level debugger indicated by the orte_base_user_debugger MCA parameter.
    --get-stack-traces
    When paired with the --timeout option, mpirun will obtainand print out stack traces from all launched processes that are still alivewhen the timeout expires. Note that obtaining stack traces can take a littletime and produce a lot of output, especially for large process-count jobs.
    -debugger, --debugger <args>
    Sequence of debuggers to search for when --debugis used (i.e. a synonym for orte_base_user_debugger MCA parameter).
    --timeout<seconds>
    The maximum number of seconds that mpirun (also known as mpiexec,oshrun, orterun, etc.) will run. After this many seconds, mpirun will abortthe launched job and exit with a non-zero exit status. Using --timeout canbe also useful when combined with the --get-stack-traces option.
    -tv, --tv
    Launchprocesses under the TotalView debugger. Deprecated backwards compatibilityflag. Synonym for --debug.

    There are also other options:

    --allow-run-as-root
    Allow mpirun to run when executed by the root user (mpirun defaults toaborting when launched as the root user).
    --app <appfile>
    Provide an appfile,ignoring all other command line options.
    -cf, --cartofile <cartofile>
    Providea cartography file.
    -continuous, --continuous
    Job is to run until explicitlyterminated.
    -disable-recovery, --disable-recovery
    Disable recovery (resetsall recovery options to off).
    -do-not-launch, --do-not-launch
    Perform all necessaryoperations to prepare to launch the application, but do not actually launchit.
    -do-not-resolve, --do-not-resolve
    Do not attempt to resolve interfaces.
    -enable-recovery, --enable-recovery
    Enable recovery from process failure [Default= disabled].
    -index-argv-by-rank, --index-argv-by-rank
    Uniquely index argv[0] foreach process using its rank.
    -leave-session-attached, --leave-session-attached
    Do not detach OmpiRTE daemons used by this application. This allows errormessages from the daemons as well as the underlying environment (e.g., whenfailing to launch a daemon) to be output.
    -max-restarts, --max-restarts <num>
    Max number of times to restart a failed process.
    -ompi-server, --ompi-server<uri or file>
    Specify the URI of the Open MPI server (or the mpirun to beused as the server), the name of the file (specified as file:filename)that contains that info, or the PID (specified as pid:#) of the mpirunto be used as the server. The Open MPI server is used to support multi-applicationdata exchange via the MPI-2 MPI_Publish_name and MPI_Lookup_name functions.
    -personality, --personality <list>
    Comma-separated list of programming model,languages, and containers being used (default='ompi').
    --ppr <list>
    Comma-separatedlist of number of processes on a given resource type [default: none].
    -report-child-jobs-separately, --report-child-jobs-separately
    Return the exit statusof the primary job only.
    -report-events, --report-events <URI>
    Report eventsto a tool listening at the specified URI.
    -report-pid, --report-pid <channel>
    Print out mpirun’s PID during startup. The channel must be either a ’-’ to indicatethat the pid is to be output to stdout, a ’+’ to indicate that the pid isto be output to stderr, or a filename to which the pid is to be written.
    -report-uri, --report-uri <channel>
    Print out mpirun’s URI during startup. Thechannel must be either a ’-’ to indicate that the URI is to be output to stdout,a ’+’ to indicate that the URI is to be output to stderr, or a filename towhich the URI is to be written.
    -show-progress, --show-progress
    Output a briefperiodic report on launch progress.
    -terminate, --terminate
    Terminate theDVM.
    -use-hwthread-cpus, --use-hwthread-cpus
    Use hardware threads as independentcpus.
    -use-regexp, --use-regexp
    Use regular expressions for launch.

    Thefollowing options are useful for developers; they are not generally usefulto most ORTE and/or MPI users:

    -d, --debug-devel
    Enable debugging of the OmpiRTE(the run-time layer in Open MPI). This is not generally useful for most users.
    --debug-daemons
    Enable debugging of any OmpiRTE daemons used by this application.
    --debug-daemons-file
    Enable debugging of any OmpiRTE daemons used by thisapplication, storing output in files.
    -display-devel-allocation, --display-devel-allocation
    Display a detailed list of the allocation being used by this job.
    -display-devel-map,--display-devel-map
    Display a more detailed table showing the mapped locationof each process prior to launch.
    -display-diffable-map, --display-diffable-map
    Display a diffable process map just before launch.
    -display-topo, --display-topo
    Display the topology as part of the process map just before launch.
    -launch-agent,--launch-agent
    Name of the executable that is to be used to start processeson the remote nodes. The default is 'orted'. This option can be used to testnew daemon concepts, or to pass options back to the daemons without havingmpirun itself see them. For example, specifying a launch agent of orted-mca odls_base_verbose 5 allows the developer to ask the orted for debuggingoutput without clutter from mpirun itself.
    --report-state-on-timeout
    When pairedwith the --timeout command line option, report the run-time subsystem stateof each process when the timeout expires.

    There may be other options listedwith mpirun --help.

    Environment Variables

    MPIEXEC_TIMEOUT
    Synonym for the--timeout command line option.

    Description

    One invocation of mpirun startsan MPI application running under Open MPI. If the application is singleprocess multiple data (SPMD), the application can be specified on the mpiruncommand line.

    If the application is multiple instruction multiple data(MIMD), comprising of multiple programs, the set of programs and argumentcan be specified in one of two ways: Extended Command Line Arguments, andApplication Context.

    An application context describes the MIMD program setincluding all arguments in a separate file. This file essentially containsmultiple mpirun command lines, less the command name itself. The abilityto specify different options for different instantiations of a programis another reason to use an application context.

    Extended command line argumentsallow for the description of the application layout on the command lineusing colons (:) to separate the specification of programs and arguments.Some options are globally set across all specified programs (e.g. --hostfile),while others are specific to a single program (e.g. -np).

    Specifying HostNodes

    Host nodes can be identified on the mpirun command line with the-host option or in a hostfile.

    For example,

    mpirun -H aa,aa,bb ./a.out
    launchestwo processes on node aa and one on bb.

    Or, consider the hostfile

    % cat myhostfile
    aa slots=2
    bb slots=2
    cc slots=2

    Here, we list both the host names (aa, bb, and cc) but also how many'slots' there are for each. Slots indicate how many processes can potentiallyexecute on a node. For best performance, the number of slots may be chosento be the number of cores on the node or the number of processor sockets. If the hostfile does not provide slots information, Open MPI will attemptto discover the number of cores (or hwthreads, if the use-hwthreads-as-cpusoption is set) and set the number of slots to that value. This default behavioralso occurs when specifying the -host option with a single hostname. Thus,the command

    mpirun -H aa ./a.out
    launches a number of processes equal tothe number of cores on node aa.
    mpirun -hostfile myhostfile ./a.out
    willlaunch two processes on each of the three nodes.
    mpirun -hostfile myhostfile-host aa ./a.out
    will launch two processes, both on node aa.
    mpirun -hostfilemyhostfile -host dd ./a.out
    will find no hosts to run on and abort with anerror. That is, the specified host dd is not in the specified hostfile.

    When running under resource managers (e.g., SLURM, Torque, etc.), Open MPIwill obtain both the hostnames and the number of slots directly from theresource manger.

    Specifying Number of Processes

    As we have just seen, thenumber of processes to run can be set using the hostfile. Other mechanismsexist.

    The number of processes launched can be specified as a multipleof the number of nodes or processor sockets available. For example,

    mpirun-H aa,bb -npersocket 2 ./a.out
    launches processes 0-3 on node aa and process4-7 on node bb, where aa and bb are both dual-socket nodes. The -npersocketoption also turns on the -bind-to-socket option, which is discussed in a latersection.
    mpirun -H aa,bb -npernode 2 ./a.out
    launches processes 0-1 on nodeaa and processes 2-3 on node bb.
    mpirun -H aa,bb -npernode 1 ./a.out
    launchesone process per host node.
    mpirun -H aa,bb -pernode ./a.out
    is the same as-npernode 1.

    Another alternative is to specify the number of processeswith the -np option. Consider now the hostfile

    % cat myhostfile
    aa slots=4
    bb slots=4
    cc slots=4

    Now,

    mpirun -hostfile myhostfile -np 6 ./a.out
    will launch processes 0-3on node aa and processes 4-5 on node bb. The remaining slots in the hostfilewill not be used since the -np option indicated that only 6 processes shouldbe launched.

    Mapping Processes to Nodes: Using Policies

    The examples aboveillustrate the default mapping of process processes to nodes. This mappingcan also be controlled with various mpirun options that describe mappingpolicies.

    Consider the same hostfile as above, again with -np 6:

    node aa node bb node cc

    mpirun 0 1 2 3 4 5

    mpirun --map-by node 0 3 1 4 2 5

    mpirun -nolocal 0 1 2 3 4 5

    The --map-by node option will load balance the processes across the availablenodes, numbering each process in a round-robin fashion.

    The -nolocal optionprevents any processes from being mapped onto the local host (in this casenode aa). While mpirun typically consumes few system resources, -nolocalcan be helpful for launching very large jobs where mpirun may actuallyneed to use noticeable amounts of memory and/or processing time.

    Just as-np can specify fewer processes than there are slots, it can also oversubscribethe slots. For example, with the same hostfile:

    mpirun -hostfile myhostfile-np 14 ./a.out
    will launch processes 0-3 on node aa, 4-7 on bb, and 8-11 on cc. It will then add the remaining two processes to whichever nodes it chooses.

    One can also specify limits to oversubscription. For example, with thesame hostfile:

    mpirun -hostfile myhostfile -np 14 -nooversubscribe ./a.out
    will produce an error since -nooversubscribe prevents oversubscription.

    Limits to oversubscription can also be specified in the hostfile itself: % cat myhostfile
    aa slots=4 max_slots=4
    bb max_slots=4
    cc slots=4

    The max_slots field specifies such a limit. When it does, the slots valuedefaults to the limit. Now:

    mpirun -hostfile myhostfile -np 14 ./a.out
    causesthe first 12 processes to be launched as before, but the remaining twoprocesses will be forced onto node cc. The other two nodes are protectedby the hostfile against oversubscription by this job.

    Using the --nooversubscribeoption can be helpful since Open MPI currently does not get 'max_slots'values from the resource manager.

    Of course, -np can also be used with the-H or -host option. For example,

    mpirun -H aa,bb -np 8 ./a.out
    launches 8 processes. Since only two hosts are specified, after the first two processes aremapped, one to aa and one to bb, the remaining processes oversubscribethe specified hosts.

    And here is a MIMD example:

    mpirun -H aa -np 1 hostname: -H bb,cc -np 2 uptime
    will launch process 0 running hostname on node aaand processes 1 and 2 each running uptime on nodes bb and cc, respectively.

    Mapping, Ranking, and Binding: Oh My!

    Open MPI employs a three-phase procedurefor assigning process locations and ranks:
    mapping
    Assigns a default locationto each process
    ranking
    Assigns an MPI_COMM_WORLD rank value to each process
    binding
    Constrains each process to run on specific processors

    The mappingstep is used to assign a default location to each process based on themapper being employed. Mapping by slot, node, and sequentially results inthe assignment of the processes to the node level. In contrast, mappingby object, allows the mapper to assign the process to an actual objecton each node.

    Note: the location assigned to the process is independentof where it will be bound - the assignment is used solely as input to thebinding algorithm.

    The mapping of process processes to nodes can be definednot just with general policies but also, if necessary, using arbitrarymappings that cannot be described by a simple policy. One can use the 'sequentialmapper,' which reads the hostfile line by line, assigning processes tonodes in whatever order the hostfile specifies. Use the -mca rmaps seq option. For example, using the same hostfile as before:

    mpirun -hostfile myhostfile-mca rmaps seq ./a.out

    will launch three processes, one on each of nodesaa, bb, and cc, respectively. The slot counts don’t matter; one processis launched per line on whatever node is listed on the line.

    Another wayto specify arbitrary mappings is with a rankfile, which gives you detailedcontrol over process binding as well. Rankfiles are discussed below.

    Thesecond phase focuses on the ranking of the process within the job’s MPI_COMM_WORLD. Open MPI separates this from the mapping procedure to allow more flexibilityin the relative placement of MPI processes. This is best illustrated byconsidering the following two cases where we used the —map-by ppr:2:socketoption:

    node aa node bb

    rank-by core 0 1 ! 2 3 4 5 ! 6 7

    rank-by socket 0 2 ! 1 3 4 6 ! 5 7

    rank-by socket:span 0 4 ! 1 5 2 6 ! 3 7

    Ranking by core and by slot provide the identical result - a simple progressionof MPI_COMM_WORLD ranks across each node. Ranking by socket does a round-robinranking within each node until all processes have been assigned an MCWrank, and then progresses to the next node. Adding the span modifier tothe ranking directive causes the ranking algorithm to treat the entireallocation as a single entity - thus, the MCW ranks are assigned acrossall sockets before circling back around to the beginning.

    The binding phaseactually binds each process to a given set of processors. This can improveperformance if the operating system is placing processes suboptimally.For example, it might oversubscribe some multi-core processor sockets, leavingother sockets idle; this can lead processes to contend unnecessarily forcommon resources. Or, it might spread processes out too widely; this canbe suboptimal if application performance is sensitive to interprocess communicationcosts. Binding can also keep the operating system from migrating processesexcessively, regardless of how optimally those processes were placed tobegin with.

    The processors to be used for binding can be identified interms of topological groupings - e.g., binding to an l3cache will bind eachprocess to all processors within the scope of a single L3 cache withintheir assigned location. Thus, if a process is assigned by the mapper toa certain socket, then a —bind-to l3cache directive will cause the processto be bound to the processors that share a single L3 cache within thatsocket.

    To help balance loads, the binding directive uses a round-robinmethod when binding to levels lower than used in the mapper. For example,consider the case where a job is mapped to the socket level, and then boundto core. Each socket will have multiple cores, so if multiple processesare mapped to a given socket, the binding algorithm will assign each processlocated to a socket to a unique core in a round-robin manner.

    Alternatively,processes mapped by l2cache and then bound to socket will simply be boundto all the processors in the socket where they are located. In this manner,users can exert detailed control over relative MCW rank location and binding.

    Finally, --report-bindings can be used to report bindings.

    As an example,consider a node with two processor sockets, each comprising four cores. We run mpirun with -np 4 --report-bindings and the following additional options:

    % mpirun ... --map-by core --bind-to core
    [...] ... binding child [...,0] to cpus 0001
    [...] ... binding child [...,1] to cpus 0002
    [...] ... binding child [...,2] to cpus 0004
    [...] ... binding child [...,3] to cpus 0008

    % mpirun ... --map-by socket --bind-to socket
    [...] ... binding child [...,0] to socket 0 cpus 000f
    [...] ... binding child [...,1] to socket 1 cpus 00f0
    [...] ... binding child [...,2] to socket 0 cpus 000f
    [...] ... binding child [...,3] to socket 1 cpus 00f0

    % mpirun ... --map-by core:PE=2 --bind-to core
    [...] ... binding child [...,0] to cpus 0003
    [...] ... binding child [...,1] to cpus 000c
    [...] ... binding child [...,2] to cpus 0030
    [...] ... binding child [...,3] to cpus 00c0

    % mpirun ... --bind-to none

    Here, --report-bindings shows the binding of each process as a mask. In thefirst case, the processes bind to successive cores as indicated by themasks 0001, 0002, 0004, and 0008. In the second case, processes bind toall cores on successive sockets as indicated by the masks 000f and 00f0.The processes cycle through the processor sockets in a round-robin fashionas many times as are needed. In the third case, the masks show us that2 cores have been bound per process. In the fourth case, binding is turnedoff and no bindings are reported.

    Open MPI’s support for process bindingdepends on the underlying operating system. Therefore, certain processbinding options may not be available on every system.

    Process binding canalso be set with MCA parameters. Their usage is less convenient than thatof mpirun options. On the other hand, MCA parameters can be set not onlyon the mpirun command line, but alternatively in a system or user mca-params.conffile or as environment variables, as described in the MCA section below.Some examples include:

    mpirun option MCA parameter key value

    --map-by core rmaps_base_mapping_policy core
    --map-by socket rmaps_base_mapping_policy socket
    --rank-by core rmaps_base_ranking_policy core
    --bind-to core hwloc_base_binding_policy core
    --bind-to socket hwloc_base_binding_policy socket
    --bind-to none hwloc_base_binding_policy none

    Rankfiles

    Rankfiles are text files that specify detailed informationabout how individual processes should be mapped to nodes, and to whichprocessor(s) they should be bound. Each line of a rankfile specifies thelocation of one process (for MPI jobs, the process’ 'rank' refers to itsrank in MPI_COMM_WORLD). The general form of each line in the rankfileis:

    rank <N>=<hostname> slot=<slot list>

    For example:

    $ cat myrankfile
    rank 0=aa slot=1:0-2
    rank 1=bb slot=0:0,1
    rank 2=cc slot=1-2
    $ mpirun -H aa,bb,cc,dd -rf myrankfile ./a.out

    Means that

    Rank 0 runs on node aa, bound to logical socket 1, cores0-2.
    Rank 1 runs on node bb, bound to logical socket 0, cores 0 and 1.
    Rank 2 runs on node cc, bound to logical cores 1 and 2.

    Rankfiles can alternatively be used to specify physical processor locations.In this case, the syntax is somewhat different. Sockets are no longer recognized,and the slot number given must be the number of the physical PU as mostOS’s do not assign a unique physical identifier to each core in the node.Thus, a proper physical rankfile looks something like the following:

    $ cat myphysicalrankfile
    rank 0=aa slot=1
    rank 1=bb slot=8
    rank 2=cc slot=6

    This means that

    Rank 0 will run on node aa, bound to the core thatcontains physical PU 1
    Rank 1 will run on node bb, bound to the core that contains physicalPU 8
    Rank 2 will run on node cc, bound to the core that contains physicalPU 6

    Rankfiles are treated as logical by default, and the MCA parameter rmaps_rank_file_physicalmust be set to 1 to indicate that the rankfile is to be considered as physical.

    The hostnames listed above are 'absolute,' meaning that actual resolveablehostnames are specified. However, hostnames can also be specified as 'relative,'meaning that they are specified in relation to an externally-specified listof hostnames (e.g., by mpirun’s --host argument, a hostfile, or a job scheduler).

    The 'relative' specification is of the form '+n<X>', where X is an integerspecifying the Xth hostname in the set of all available hostnames, indexedfrom 0. For example:

    $ cat myrankfile
    rank 0=+n0 slot=1:0-2
    rank 1=+n1 slot=0:0,1
    rank 2=+n2 slot=1-2
    $ mpirun -H aa,bb,cc,dd -rf myrankfile ./a.out

    Starting with Open MPI v1.7, all socket/core slot locations are be specifiedas logical indexes (the Open MPI v1.6 series used physical indexes). Youcan use tools such as HWLOC’s 'lstopo' to find the logical indexes of socketand cores.

    Application Context or Executable Program?

    To distinguish thetwo different forms, mpirun looks on the command line for --app option. Ifit is specified, then the file named on the command line is assumed tobe an application context. If it is not specified, then the file is assumedto be an executable program.

    Locating Files

    If no relative or absolutepath is specified for a file, Open MPI will first look for files by searchingthe directories specified by the --path option. If there is no --path optionset or if the file is not found at the --path location, then Open MPI willsearch the user’s PATH environment variable as defined on the source node(s).

    If a relative directory is specified, it must be relative to the initialworking directory determined by the specific starter used. For example whenusing the rsh or ssh starters, the initial directory is $HOME by default.Other starters may set the initial directory to the current working directoryfrom the invocation of mpirun.

    Current Working Directory

    The -wdir mpirunoption (and its synonym, -wd) allows the user to change to an arbitrarydirectory before the program is invoked. It can also be used in applicationcontext files to specify working directories on specific nodes and/or forspecific applications.

    If the -wdir option appears both in a context fileand on the command line, the context file directory will override the commandline value.

    If the -wdir option is specified, Open MPI will attempt to changeto the specified directory on all of the remote nodes. If this fails, mpirunwill abort.

    If the -wdir option is not specified, Open MPI will send thedirectory name where mpirun was invoked to each of the remote nodes. Theremote nodes will try to change to that directory. If they are unable (e.g.,if the directory does not exist on that node), then Open MPI will use thedefault directory determined by the starter.

    All directory changing occursbefore the user’s program is invoked; it does not wait until MPI_INIT iscalled.

    Standard I/O

    Open MPI directs UNIX standard input to /dev/nullon all processes except the MPI_COMM_WORLD rank 0 process. The MPI_COMM_WORLDrank 0 process inherits standard input from mpirun. Note: The node thatinvoked mpirun need not be the same as the node where the MPI_COMM_WORLDrank 0 process resides. Open MPI handles the redirection of mpirun’s standardinput to the rank 0 process.

    Open MPI directs UNIX standard output and errorfrom remote nodes to the node that invoked mpirun and prints it on thestandard output/error of mpirun. Local processes inherit the standard output/errorof mpirun and transfer to it directly.

    Thus it is possible to redirect standardI/O for Open MPI applications by using the typical shell redirection procedureon mpirun.

    % mpirun -np 2 my_app < my_input > my_output

    Note that in this example only the MPI_COMM_WORLD rank 0 process willreceive the stream from my_input on stdin. The stdin on all the other nodeswill be tied to /dev/null. However, the stdout from all nodes will be collectedinto the my_output file.

    Signal Propagation

    When orterun receives a SIGTERMand SIGINT, it will attempt to kill the entire job by sending all processesin the job a SIGTERM, waiting a small number of seconds, then sending allprocesses in the job a SIGKILL.

    SIGUSR1 and SIGUSR2 signals received byorterun are propagated to all processes in the job.

    A SIGTSTOP signal tompirun will cause a SIGSTOP signal to be sent to all of the programs startedby mpirun and likewise a SIGCONT signal to mpirun will cause a SIGCONTsent.

    Other signals are not currently propagated by orterun.

    Process Termination/ Signal Handling

    During the run of an MPI application, if any processdies abnormally (either exiting before invoking MPI_FINALIZE, or dyingas the result of a signal), mpirun will print out an error message andkill the rest of the MPI application.

    User signal handlers should probablyavoid trying to cleanup MPI state (Open MPI is currently not async-signal-safe;see MPI_Init_thread(3) for details about MPI_THREAD_MULTIPLE and threadsafety). For example, if a segmentation fault occurs in MPI_SEND (perhapsbecause a bad buffer was passed in) and a user signal handler is invoked,if this user handler attempts to invoke MPI_FINALIZE, Bad Things couldhappen since Open MPI was already 'in' MPI when the error occurred. Sincempirun will notice that the process died due to a signal, it is probablynot necessary (and safest) for the user to only clean up non-MPI state.

    Process Environment

    Processes in the MPI application inherit their environmentfrom the Open RTE daemon upon the node on which they are running. The environmentis typically inherited from the user’s shell. On remote nodes, the exactenvironment is determined by the boot MCA module used. The rsh launch module,for example, uses either rsh/ssh to launch the Open RTE daemon on remotenodes, and typically executes one or more of the user’s shell-setup filesbefore launching the Open RTE daemon. When running dynamically linked applicationswhich require the LD_LIBRARY_PATH environment variable to be set, caremust be taken to ensure that it is correctly set when booting Open MPI.

    See the 'Remote Execution' section for more details.

    Remote Execution

    Open MPI requires that the PATH environment variable be set to find executableson remote nodes (this is typically only necessary in rsh- or ssh-based environments-- batch/scheduled environments typically copy the current environment tothe execution of remote jobs, so if the current environment has PATH and/orLD_LIBRARY_PATH set properly, the remote nodes will also have it set properly). If Open MPI was compiled with shared library support, it may also be necessaryto have the LD_LIBRARY_PATH environment variable set on remote nodes aswell (especially to find the shared libraries required to run user MPIapplications).

    However, it is not always desirable or possible to edit shellstartup files to set PATH and/or LD_LIBRARY_PATH. The --prefix option isprovided for some simple configurations where this is not possible.

    The--prefix option takes a single argument: the base directory on the remotenode where Open MPI is installed. Open MPI will use this directory to setthe remote PATH and LD_LIBRARY_PATH before executing any Open MPI or userapplications. This allows running Open MPI jobs without having pre-configuredthe PATH and LD_LIBRARY_PATH on the remote nodes.

    Open MPI adds the basenameof the current node’s 'bindir' (the directory where Open MPI’s executablesare installed) to the prefix and uses that to set the PATH on the remotenode. Similarly, Open MPI adds the basename of the current node’s 'libdir'(the directory where Open MPI’s libraries are installed) to the prefix anduses that to set the LD_LIBRARY_PATH on the remote node. For example:

    Localbindir:
    /local/node/directory/bin
    Local libdir:
    /local/node/directory/lib64

    If the following command line is used:

    % mpirun --prefix /remote/node/directory

    Open MPI will add '/remote/node/directory/bin' to the PATH and '/remote/node/directory/lib64'to the LD_LIBRARY_PATH on the remote node before attempting to executeanything.

    The --prefix option is not sufficient if the installation pathson the remote node are different than the local node (e.g., if '/lib' isused on the local node, but '/lib64' is used on the remote node), or ifthe installation paths are something other than a subdirectory under acommon prefix.

    Note that executing mpirun via an absolute pathname is equivalentto specifying --prefix without the last subdirectory in the absolute pathnameto mpirun. For example:

    % /usr/local/bin/mpirun ...

    is equivalent to

    % mpirun --prefix /usr/local

    Exported Environment Variables

    All environment variables that are namedin the form OMPI_* will automatically be exported to new processes on thelocal and remote nodes. Environmental parameters can also be set/forwardedto the new processes using the MCA parameter mca_base_env_list. The -x optionto mpirun has been deprecated, but the syntax of the MCA param followsthat prior example. While the syntax of the -x option and MCA param allowsthe definition of new variables, note that the parser for these optionsare currently not very sophisticated - it does not even understand quotedvalues. Users are advised to set variables in the environment and use theoption to export them; not to define them.

    Setting MCA Parameters

    The-mca switch allows the passing of parameters to various MCA (Modular ComponentArchitecture) modules. MCA modules have direct impact on MPI programs becausethey allow tunable parameters to be set at run time (such as which BTLcommunication device driver to use, what parameters to pass to that BTL,etc.).

    The -mca switch takes two arguments: <key> and <value>. The <key> argumentgenerally specifies which MCA module will receive the value. For example,the <key> 'btl' is used to select which BTL to be used for transporting MPImessages. The <value> argument is the value that is passed. For example:

    mpirun -mca btl tcp,self -np 1 foo
    Tells Open MPI to use the 'tcp' and 'self'BTLs, and to run a single copy of 'foo' an allocated node.
    mpirun -mca btlself -np 1 foo
    Tells Open MPI to use the 'self' BTL, and to run a singlecopy of 'foo' an allocated node.

    The -mca switch can be used multiple timesto specify different <key> and/or <value> arguments. If the same <key> is specifiedmore than once, the <value>s are concatenated with a comma (',') separatingthem.

    Note that the -mca switch is simply a shortcut for setting environmentvariables. The same effect may be accomplished by setting correspondingenvironment variables before running mpirun. The form of the environmentvariables that Open MPI sets is:

    OMPI_MCA_<key>=<value>

    Thus, the -mca switch overrides any previously set environment variables. The -mca settings similarly override MCA parameters set in the $OPAL_PREFIX/etc/openmpi-mca-params.confor $HOME/.openmpi/mca-params.conf file.

    Unknown <key> arguments are still setas environment variable -- they are not checked (by mpirun) for correctness.Illegal or incorrect <value> arguments may or may not be reported -- it dependson the specific MCA module.

    To find the available component types underthe MCA architecture, or to find the available parameters for a specificcomponent, use the ompi_info command. See the ompi_info(1) man page fordetailed information on the command.

    Setting MCA parameters and environmentvariables from file.

    The -tune command line option and its synonym -mca mca_base_envar_file_prefixallows a user to set mca parameters and environment variables with thesyntax described below. This option requires a single file or list of filesseparated by ',' to follow.

    A valid line in the file may contain zero ormany '-x', '-mca', or “--mca” arguments. The following patterns are supported:-mca var val -mca var 'val' -x var=val -x var. If any argument is duplicatedin the file, the last value read will be used.

    MCA parameters and environmentspecified on the command line have higher precedence than variables specifiedin the file.

    Running as root

    The Open MPI team strongly advises againstexecuting mpirun as the root user. MPI applications should be run as regular(non-root) users.

    Reflecting this advice, mpirun will refuse to run as rootby default. To override this default, you can add the --allow-run-as-root optionto the mpirun command line.

    Exit status

    There is no standard definitionfor what mpirun should return as an exit status. After considerable discussion,we settled on the following method for assigning the mpirun exit status(note: in the following description, the 'primary' job is the initial applicationstarted by mpirun - all jobs that are spawned by that job are designated'secondary' jobs):
    [bu]
    if all processes in the primary job normally terminatewith exit status 0, we return 0
    [bu]
    if one or more processes in the primaryjob normally terminate with non-zero exit status, we return the exit statusof the process with the lowest MPI_COMM_WORLD rank to have a non-zero status
    [bu]
    if all processes in the primary job normally terminate with exit status0, and one or more processes in a secondary job normally terminate withnon-zero exit status, we (a) return the exit status of the process withthe lowest MPI_COMM_WORLD rank in the lowest jobid to have a non-zero status,and (b) output a message summarizing the exit status of the primary andall secondary jobs.
    [bu]
    if the cmd line option --report-child-jobs-separatelyis set, we will return -only- the exit status of the primary job. Any non-zeroexit status in secondary jobs will be reported solely in a summary printstatement.

    By default, OMPI records and notes that MPI processes exitedwith non-zero termination status. This is generally not considered an 'abnormaltermination' - i.e., OMPI will not abort an MPI job if one or more processesreturn a non-zero status. Instead, the default behavior simply reports thenumber of processes terminating with non-zero status upon completion ofthe job.

    However, in some cases it can be desirable to have the job abortwhen any process terminates with non-zero status. For example, a non-MPI jobmight detect a bad result from a calculation and want to abort, but doesn’twant to generate a core file. Or an MPI job might continue past a call toMPI_Finalize, but indicate that all processes should abort due to somepost-MPI result.

    It is not anticipated that this situation will occur frequently.However, in the interest of serving the broader community, OMPI now hasa means for allowing users to direct that jobs be aborted upon any processexiting with non-zero status. Setting the MCA parameter 'orte_abort_on_non_zero_status'to 1 will cause OMPI to abort all processes once any process exits withnon-zero status.

    Terminations caused in this manner will be reported on the console asan 'abnormal termination', with the first process to so exit identifiedalong with its exit status.

    Examples

    Be sure also to see the examplesthroughout the sections above.
    mpirun -np 4 -mca btl ib,tcp,self prog1
    Run4 copies of prog1 using the 'ib', 'tcp', and 'self' BTL’s for the transportof MPI messages.
    mpirun -np 4 -mca btl tcp,sm,self

    --mca btl_tcp_if_include eth0 prog1
    Run 4 copies of prog1 using the 'tcp', 'sm' and 'self' BTLs for the transportof MPI messages, with TCP using only the eth0 interface to communicate. Note that other BTLs have similar if_include MCA parameters.

    Return Value

    mpirun returns 0 if all processes started by mpirun exitafter calling MPI_FINALIZE. A non-zero value is returned if an internalerror occurred in mpirun, or one or more processes exited before callingMPI_FINALIZE. If an internal error occurred in mpirun, the correspondingerror code is returned. In the event that one or more processes exit beforecalling MPI_FINALIZE, the return value of the MPI_COMM_WORLD rank of theprocess that mpirun first notices died before calling MPI_FINALIZE willbe returned. Note that, in general, this will be the first process thatdied but is not guaranteed to be so.

    If the --timeout command line optionis used and the timeout expires before the job completes (thereby forcingmpirun to kill the job) mpirun will return an exit status equivalent tothe value of ETIMEDOUT (which is typically 110 on Linux and OS X systems).

    See Also

    MPI_Init_thread(3)

    Abstract

    The ThinkSystem SR650 is a mainstream 2U 2-socket server with industry-leading reliability, management, and security features, and is designed to handle a wide range of workloads.

    New to the SR650 is support for up to 24 NVMe solid-state drives. With this support, the SR650 is an excellent choice for workloads that need large amounts of low-latency high-bandwidth storage, including virtualized clustered SAN solutions, software-defined storage, and applications leveraging NVMe over Fabrics (NVMeOF).

    This article describes the three new configurations available for the SR650:

    • 16 NVMe drives + 8 SAS/SATA drives
    • 20 NVMe drives
    • 24 NVMe drives

    You can also learn about the offerings by watching the walk-through video below.

    Change History

    Changes in the April 16 update:

    • Noted which second-generation Intel Xeon processors are not supported - Ordering information section

    Walk-through video with David Watts and Patrick Caporale

    Introduction

    The Lenovo ThinkSystem SR650 is a mainstream 2U 2-socket server with industry-leading reliability, management, and security features, and is designed to handle a wide range of workloads.

    New to the SR650 is support for up to 24 NVMe solid-state drives. With this support, the SR650 is an excellent choice for workloads that need large amounts of low-latency high-bandwidth storage, including virtualized clustered SAN solutions, software-defined storage, and applications leveraging NVMe over Fabrics (NVMeOF).


    Figure 1. ThinkSystem SR650 with 24 NVMe drives

    Three new configurations are now available:

    • 16 NVMe drives + 8 SAS/SATA drives
    • 20 NVMe drives
    • 24 NVMe drives

    NVMe (Non-Volatile Memory Express) is a technology that overcomes SAS/SATA SSD performance limitations by optimizing hardware and software to take full advantage of flash technology. Intel Xeon processors efficiently transfer data in fewer clock cycles with the NVMe optimized software stack compared to the legacy AHCI stack, thereby reducing latency and overhead. NVMe SSDs connect directly to the processor via the PCIe bus, further reducing latency. NVMe drives are characterized by very high bandwidth and very low latency.

    Ordering information

    These configurations are available configure-to-order (CTO) in the Lenovo Data Center Solution Configurator (DCSC), https://dcsc.lenovo.com. The following table lists the feature codes related to the NVMe drive subsystem. The configurator will derive any additional components that are needed.

    Field upgrades: The 20x NVMe and 24x NVMe drive configurations are also available as field upgrades as described in the Field upgrades section.

    Table 1. Feature codes for CTO orders
    Feature codeDescription
    PCIe Switch Adapters
    B22DThinkSystem 810-4P NVMe Switch Adapter
    (PCIe x8 adapter with four x4 drive connectors)
    AUV2ThinkSystem 1610-4P NVMe Switch Adapter
    (PCIe x16 adapter with four x4 drive connectors)
    B4PAThinkSystem 1610-8P NVMe Switch Adapter
    (PCIe x16 adapter with four connectors to connect to eight drives)
    NVMe Backplane
    B4PCThinkSystem SR650 2.5' NVMe 8-Bay Backplane
    Riser Cards
    AUR3ThinkSystem SR550/SR590/SR650 x16/x8 PCIe FH Riser 1 Kit
    (x16+x8 PCIe Riser for Riser 1, for 16 and 20-drive configurations)
    B4PBThinkSystem SR650 x16/x8/x16 PCIe Riser1
    (x16+x8+x16 PCIe Riser for Riser 1, for 24-drive configurations)
    AURCThinkSystem SR550/SR590/SR650 (x16/x8)/(x16/x16) PCIe FH Riser 2 Kit
    (x16+x16 PCIe Riser for Riser 2, for all three configurations)

    Note the following requirements for any of the three NVMe-rich configurations:

    • Two processors
    • No high-thermal processors:
      • 200 W or 205 W TDP are not supported
      • Gold 6126T, Gold 6144, Gold 6146, or Platinum 8160T processors are not supported
      • Gold 6230N, Gold 6240Y, and Gold 6244 processors are not supported
    • No GPU adapters installed
    • No PCIe flash adapters installed
    • No PCIe adapters with more than 25 W TDP installed
    • 1100 W or 1600 W power supplies installed.
    • Ambient temperature of up to 30 °C (86 °F)
    • If a fan fails and the ambient temperature is above 27 °C, system performance may be reduced.

    Although not required, it is expected that these configurations will be fully populated with NVMe drives. Maximum performance is achieved when all NVMe drive bays are filled with drives.

    To verify support and ensure that the right power supply is chosen for optimal performance, validate your server configuration using the latest version of the Lenovo Capacity Planner:
    http://datacentersupport.lenovo.com/us/en/solutions/lnvo-lcp

    Supported NVMe drives

    See the ThinkSystem SR650 product guide for the complete list of NVMe drives that are supported in the server: https://lenovopress.com/lp0644#drives-for-internal-storage

    The NVMe drives listed in the following table are not supported in the three NVMe-rich configurations.

    Table 2. NVMe drives that are not supported in the 16, 20, and 24x NVMe drive configurations
    Part numberFeature codeDescription
    Unsupported NVMe drives
    7SD7A05770B11LThinkSystem U.2 Intel P4600 6.4TB Mainstream NVMe PCIe3.0 x4 Hot Swap SSD
    7N47A00984AUV0ThinkSystem U.2 PM963 1.92TB Entry NVMe PCIe 3.0 x4 Hot Swap SSD
    7N47A00985AUUUThinkSystem U.2 PM963 3.84TB Entry NVMe PCIe 3.0 x4 Hot Swap SSD
    7N47A00095AUUYThinkSystem U.2 PX04PMB 960GB Mainstream NVMe PCIe 3.0 x4 Hot Swap SSD
    7N47A00096AUMFThinkSystem U.2 PX04PMB 1.92TB Mainstream NVMe PCIe 3.0 x4 Hot Swap SSD
    7XB7A05923AWG6ThinkSystem U.2 PX04PMB 800GB Performance NVMe PCIe 3.0 x4 Hot Swap SSD
    7XB7A05922AWG7ThinkSystem U.2 PX04PMB 1.6TB Performance NVMe PCIe 3.0 x4 Hot Swap SSD

    Configuration 1: 16x NVMe drives + 8x SAS/SATA

    The 16x NVMe drive configuration has the following features:

    • 16 NVMe 2.5-inch drive bays plus eight SAS/SATA 2.5-inch drive bays. All drives are hot-swap from the front of the server (provided the operating system supports hot-swap).
    • The NVMe drives are connected to the processors either via NVMe Switch Adapters or via the onboard NVMe connectors on the system board of the server.
    • The eight SAS/SATA drive bays are connected to a supported 8-port RAID adapter or SAS HBA.
    • One PCIe x16 slot is available for high-speed networking such as a 100 GbE adapter, InfiniBand or OPA adapter. If you elect not to configure the eight SAS/SATA drive bays, then you can free up an additional x8 slot for a second networking adapter.
    • The LOM (LAN on Motherboard) slot is also available for 1Gb or 10Gb Ethernet connections. Supported LOM adapters are the following:
      • ThinkSystem 1Gb 2-port RJ45 LOM
      • ThinkSystem 1Gb 4-port RJ45 LOM
      • ThinkSystem 10Gb 2-port Base-T LOM
      • ThinkSystem 10Gb 2-port SFP+ LOM
      • ThinkSystem 10Gb 4-port Base-T LOM
      • ThinkSystem 10Gb 4-port SFP+ LOM
    • Additional support for one or two M.2 drives, if needed

    The 16x NVMe drive configuration has the following performance characteristics:

    • Balanced NVMe configuration. In this 16-NVMe drive configuration, each processor is connected to 8 drives. Such a balanced configuration ensures maximum performance by ensuring the processors are equally occupied handling I/O requests to and from the NVMe drives.
    • No oversubscription. Lenovo NVMe drives connect using four PCIe lanes, and in this configuration, each drive is allocated 4 lanes from the processor. The 1:1 ratio means no oversubscription of the PCIe lanes from the processors and results in maximum NVMe drive bandwidth.

    In the 16x NVMe drive configuration, the drive bays are configured as follows:

    • Bays 0-15: NVMe drives
    • Bays 16-23: SAS or SATA drives

    The PCIe slots in the server are configured as follows:

    • Slot 1: 1610-4P NVMe Switch Adapter
    • Slot 2: Not present
    • Slot 3: Supported RAID adapter for SAS/SATA drives
    • Slot 4: 810-4P NVMe Switch Adapter
    • Slot 5: Available x16 slot
    • Slot 6: 1610-4P NVMe Switch Adapter
    • Slot 7 (internal slot): 810-4P NVMe Switch Adapter

    The front and rear views of the SR650 with 16x NVMe drives and 8x SAS/SATA drives is shown in the following figure.


    Figure 2. SR650 front and rear views of the 16-NVMe drive configuration

    The following figure shows a block diagram of how the PCIe lanes are routed from the processors to the NVMe drives.

    No Hw-module Slot 1 Oversubscription Port-group 1


    Figure 3. SR650 block diagram of the 16-NVMe drive configuration

    No Hw-module Slot 1 Oversubscription

    The details of the connections are listed in the following table.

    Table 3. Drive connections
    Drive bayDrive typeDrive lanesAdapterSlotHost lanesCPU
    0NVMePCIe x4Onboard NVMe portNonePCIe x82
    1NVMePCIe x42
    2NVMePCIe x4Onboard NVMe portNonePCIe x82
    3NVMePCIe x42
    4NVMePCIe x41610-4PSlot 6 (Riser 2)PCIe x162
    5NVMePCIe x42
    6NVMePCIe x42
    7NVMePCIe x42
    8NVMePCIe x4810-4PSlot 4 (vertical)PCIe x81
    9NVMePCIe x41
    10NVMePCIe x4810-4PSlot 7 (internal)PCIe x81
    11NVMePCIe x41
    12NVMePCIe x41610-4PSlot 1 (Riser 1)PCIe x161
    13NVMePCIe x41
    14NVMePCIe x41
    15NVMePCIe x41
    16SAS or SATARAID 8iSlot 3 (Riser 1)PCIe x81
    17SAS or SATA1
    18SAS or SATA1
    19SAS or SATA1
    20SAS or SATA1
    21SAS or SATA1
    22SAS or SATA1
    23SAS or SATA1

    Configuration 2: 20x NVMe drives

    The 20x NVMe drive configuration has the following features:

    • 20 NVMe 2.5-inch drive bays. All drives are hot-swap from the front of the server (provided the operating system supports hot-swap). The other 4 bays are unavailable and are covered by a 4-bay blank.
    • The NVMe drives are connected to the processors either via NVMe Switch Adapters or via the onboard NVMe connectors on the system board of the server.
    • One PCIe x8 slot is available for networking or other needs. The LOM (LAN on Motherboard) slot is also available for 1Gb or 10Gb Ethernet connections. Supported LOM adapters are the following:
      • ThinkSystem 1Gb 2-port RJ45 LOM
      • ThinkSystem 1Gb 4-port RJ45 LOM
      • ThinkSystem 10Gb 2-port Base-T LOM
      • ThinkSystem 10Gb 2-port SFP+ LOM
      • ThinkSystem 10Gb 4-port Base-T LOM
      • ThinkSystem 10Gb 4-port SFP+ LOM
    • Additional support for one or two M.2 drives, if needed

    The 20x NVMe drive configuration has the following performance characteristics:

    • No oversubscription. Lenovo NVMe drives connect using four PCIe lanes, and in this configuration, each drive is allocated 4 lanes from the processor. The 1:1 ratio means no oversubscription of the PCIe lanes from the processors and results in maximum NVMe drive bandwidth.
    • Near-balanced NVMe configuration. Unlike the 16-drive and 24-drive configurations, that 20-drive configuration has eight NVMe drives connected to processor 1, and 12 NVMe drives connected to processor 2. As a result, we recommend you to only choose this configuration if you need the additional capacity that four drives provide above the 16-drive configuration, and your workload can fully operate without an equal number of drives connected to each processor.

    The PCIe slots in the server are configured as follows:

    • Slot 1: 1610-4P NVMe Switch Adapter
    • Slot 2: Not present
    • Slot 3: Available x8 slot
    • Slot 4: 810-4P NVMe Switch Adapter
    • Slot 5: 1610-4P NVMe Switch Adapter
    • Slot 6: 1610-4P NVMe Switch Adapter
    • Slot 7 (internal slot): 810-4P NVMe Switch Adapter

    The front and rear views of the SR650 with 20x NVMe drives is shown in the following figure.


    Figure 4. SR650 front and rear views of the 20-NVMe drive configuration

    The following figure shows a block diagram of how the PCIe lanes are routed from the processors to the NVMe drives.


    Figure 5. SR650 block diagram of the 20-NVMe drive configuration

    The details of the connections are listed in the following table.

    Table 4. Drive connections
    Drive bayDrive typeDrive lanesAdapterSlotHost lanesCPU
    0NVMePCIe x4Onboard NVMe portNonePCIe x82
    1NVMePCIe x42
    2NVMePCIe x4Onboard NVMe portNonePCIe x82
    3NVMePCIe x42
    4NVMePCIe x41610-4PSlot 6 (Riser 2)PCIe x162
    5NVMePCIe x42
    6NVMePCIe x42
    7NVMePCIe x42
    8NVMePCIe x41610-4PSlot 5 (Riser 2)PCIe x162
    9NVMePCIe x42
    10NVMePCIe x42
    11NVMePCIe x42
    12NVMePCIe x4810-4PSlot 4 (vertical)PCIe x81
    13NVMePCIe x41
    14NVMePCIe x4810-4PSlot 7 (internal)PCIe x81
    15NVMePCIe x41
    16NVMePCIe x41610-4PSlot 1 (Riser 1)PCIe x161
    17NVMePCIe x41
    18NVMePCIe x41
    19NVMePCIe x41
    20Blank bay - no connection
    21Blank bay - no connection
    22Blank bay - no connection
    23Blank bay - no connection

    Configuration 3: 24x NVMe drives

    The 24x NVMe drive configuration has the following features:

    • 24 NVMe 2.5-inch drive bays. All drives are hot-swap from the front of the server (provided the operating system supports hot-swap).
    • The NVMe drives are connected to the processors via NVMe Switch Adapters. The onboard NVMe connectors are routed to a riser card installed in Riser slot 1.
    • Two x16 slots (one connected to each processor) are available for high-speed networking such as a 100 GbE adapter, InfiniBand or OPA adapter.
    • The LOM (LAN on Motherboard) slot is also available for 1Gb or 10Gb Ethernet connections. Supported LOM adapters are the following:
      • ThinkSystem 1Gb 2-port RJ45 LOM
      • ThinkSystem 1Gb 4-port RJ45 LOM
      • ThinkSystem 10Gb 2-port Base-T LOM
      • ThinkSystem 10Gb 2-port SFP+ LOM
      • ThinkSystem 10Gb 4-port Base-T LOM
      • ThinkSystem 10Gb 4-port SFP+ LOM
    • Additional support for one or two M.2 drives, if needed

    The 24x NVMe drive configuration has the following performance characteristics:

    Hw-module Slot 1 Oversubscription Port-group 1

    • Balanced NVMe configuration. In this 24-NVMe drive configuration, each processor is connected to 12 drives. Such a balanced configuration provides maximum performance by ensuring the processors are equally occupied handling I/O requests to and from the NVMe drives.
    • 2:1 oversubscription. Lenovo NVMe drives connect using four PCIe lanes, and in this configuration each drive is allocated 2 lanes from the processor, resulting in a 2:1 oversubscription of the PCIe lanes. With 24 drives, there are simply not enough PCIe lanes in a two-socket server to support no oversubscription. As a result, the design objective is to minimize the oversubscription while still maintaining balance across all lanes.
    • Balanced open slots. This configuration has two open PCIe x16 slots, one connected to each processor. These slots could be used for a pair of high-speed network cards and the result would be balanced configuration.

    The PCIe slots in the server are configured as follows:

    • Slot 1: 1610-8P NVMe Switch Adapter
    • Slot 2: 810-4P NVMe Switch Adapter
    • Slot 3: Available x16 slot
    • Slot 4: 810-4P NVMe Switch Adapter
    • Slot 5: Available x16 slot
    • Slot 6: 810-4P NVMe Switch Adapter
    • Slot 7 (internal slot): 810-4P NVMe Switch Adapter

    The front and rear views of the SR650 with 24x NVMe drives is shown in the following figure.


    Figure 6. SR650 front and rear views of the 24-NVMe drive configuration

    The following figure shows a block diagram of how the PCIe lanes are routed from the processors to the NVMe drives.


    Figure 7. SR650 block diagram of the 24-NVMe drive configuration

    The details of the connections are listed in the following table.

    Table 5. Drive connections
    Drive bayDrive typeDrive lanesAdapterSlotHost lanesCPU
    0NVMePCIe x4810-4PSlot 6 (Riser 2)PCIe x82
    1NVMePCIe x4
    2NVMePCIe x42
    3NVMePCIe x4
    4NVMePCIe x41610-8PSlot 1 (Riser 1)PCIe x16
    (from onboard NVMe ports)    		2
    5NVMePCIe x4
    6NVMePCIe x42
    7NVMePCIe x4
    8NVMePCIe x42
    9NVMePCIe x4
    10NVMePCIe x42
    11NVMePCIe x4
    12NVMePCIe x4810-4PSlot 4 (vertical)PCIe x81
    13NVMePCIe x4
    14NVMePCIe x41
    15NVMePCIe x4
    16NVMePCIe x4810-4PSlot 7 (internal)PCIe x81
    17NVMePCIe x4
    18NVMePCIe x41
    19NVMePCIe x4
    20NVMePCIe x4810-4PSlot 2 (Riser 1)PCIe x81
    21NVMePCIe x4
    22NVMePCIe x41
    23NVMePCIe x4

    Field upgrades

    The following two field upgrade option kits are available to upgrade existing SAS/SATA or AnyBay drive configurations based on the 24x 2.5' chassis (feature code AUVV) to either the 20-drive or 24-drive NVMe configurations.

    Table 6. Field upgrades
    Part numberFeature codeDescription
    4XH7A09819B64LThinkSystem SR650 U.2 20-Bays Upgrade Kit
    4XH7A08810B64KThinkSystem SR650 U.2 24-Bays Upgrade Kit

    These kits include drive backplanes and required NVMe cables, power cables, drive bay fillers, and NVMe switch adapters.

    No 16-drive upgrade kit: There is no upgrade kit for the 16x NVMe drive configuration.

    The ThinkSystem SR650 U.2 20-Bays Upgrade Kit includes the following components:

    • Two 810-4P NVMe Switch Adapters
    • Three 1610-4P NVMe Switch Adapters
    • One x16/x8 PCIe Riser for Riser 1
    • One x16/x16 PCIe Riser for Riser 2
    • Three 8-bay NVMe drive backplanes
    • One 4-bay drive bay filler
    • NVMe and power cables
    • Brackets and screws
    • Drive bay labels for the front bezel

    The ThinkSystem SR650 U.2 24-Bays Upgrade Kit includes the following components:

    • Four 810-4P NVMe Switch Adapters
    • One 1610-8P NVMe Switch Adapter
    • One x16/x8/x16 PCIe Riser for Riser 1
    • One x16/x16 PCIe Riser for Riser 2
    • Three 8-bay NVMe drive backplanes
    • NVMe and power cables
    • Brackets and screws
    • Drive bay labels for the front bezel

    Further information

    For more information, see these resources:

    • ThinkSystem SR650 product guide
      https://lenovopress.com/lp0644-lenovo-thinksystem-sr650-server
    • Product Guides for ThinkSystem NVMe drives:
      https://lenovopress.com/servers/options/drives#term=nvme&rt=product-guide
    • Paper, Implementing NVMe Drives on Lenovo Servers
      https://lenovopress.com/lp0508-implementing-nvme-drives-on-lenovo-servers
    • Paper, Comparing the Effect of PCIe Host Connections on NVMe Drive Performance
      https://lenovopress.com/lp0865-comparing-the-effect-of-pcie-host-connections-on-nvme-drive-performance
    • Data Center Solution Configurator (DCSC) configurator
      https://dcsc.lenovo.com/

    Related product families

    Product families related to this document are the following:

    Trademarks

    Lenovo and the Lenovo logo are trademarks or registered trademarks of Lenovo in the United States, other countries, or both. A current list of Lenovo trademarks is available on the Web at https://www.lenovo.com/us/en/legal/copytrade/.

    The following terms are trademarks of Lenovo in the United States, other countries, or both:
    Lenovo®
    AnyBay®
    ThinkSystem

    The following terms are trademarks of other companies:

    Intel® and Xeon® are trademarks of Intel Corporation or its subsidiaries.

    Other company, product, or service names may be trademarks or service marks of others.

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