NAME

       mongoperf - MongoDB

SYNOPSIS

       mongoperf is a utility to check disk I/O performance independently of MongoDB.

       It times tests of random disk I/O and presents the results. You can use mongoperf for any case apart from
       MongoDB.  The mmf true mode is completely generic. In that mode is it somewhat analogous to tools such as
       bonnie++ (albeit mongoperf is simpler).

       Specify options to mongoperf using a JavaScript document.

       See also

       • bonnie

       • bonnie++

       • Output from an example run

       • Checking Disk Performance with the mongoperf Utility

OPTIONS

       mongoperf

       --help Displays the options to mongoperf.  Specify options to mongoperf with a JSON document described in
              the Configuration Fields section.

       <jsonconfig>
              mongoperf accepts configuration options in the form of a file that holds a JSON document. You must
              stream the content of this file into mongoperf, as in the following operation:

              mongoperf < config

              In this example config is the name of a file  that  holds  a  JSON  document  that  resembles  the
              following example:

              {
                nThreads:<n>,
                fileSizeMB:<n>,
                sleepMicros:<n>,
                mmf:<bool>,
                r:<bool>,
                w:<bool>,
                recSizeKB:<n>,
                syncDelay:<n>
              }

              See the Configuration Fields section for documentation of each of these fields.

CONFIGURATION FIELDS

       mongoperf.nThreads
              Type: Integer.

              Default: 1

              Defines  the  number  of threads mongoperf will use in the test. To saturate your system's storage
              system you will need multiple threads. Consider setting nThreads to 16.

       mongoperf.fileSizeMB
              Type: Integer.

              Default: 1 megabyte (i.e. 10242 bytes)

              Test file size.

       mongoperf.sleepMicros
              Type: Integer.

              Default: 0

              mongoperf will pause for the number of specified sleepMicros divided by the nThreads between  each
              operation.

       mongoperf.mmf
              Type: Boolean.

              Default: false

              Set mmf to true to use memory mapped files for the tests.

              Generally:

              • when mmf is false, mongoperf tests direct, physical, I/O, without caching. Use a large file size
                to test heavy random I/O load and to avoid I/O coalescing.

              • when  mmf  is  true,  mongoperf runs tests of the caching system, and can use normal file system
                cache. Use mmf in this mode to test file system cache behavior with memory mapped files.

       mongoperf.r
              Type: Boolean.

              Default: false

              Set r to true to perform reads as part of the tests.

              Either r or w must be true.

       mongoperf.w
              Type: Boolean.

              Default: false

              Set w to true to perform writes as part of the tests.

              Either r or w must be true.

       mongoperf.syncDelay
              Type: Integer.

              Default: 0

              Seconds between disk flushes. syncDelay is similar to syncDelay for mongod.

              The syncDelay controls how frequently mongoperf performs an asynchronous  disk  flush  the  memory
              mapped  file  used for testing. By default, mongod performs this operation every every 60 seconds.
              Use syncDelay to test basic system performance of this type of operation.

              Only use syncDelay in conjunction with mmf set to true.

              The default value of 0 disables this

USE

       mongoperf < jsonconfigfile

       Replace jsonconfigfile with the path to the mongoperf configuration. You may also invoke mongoperf in the
       following form:

       echo "{nThreads:16,fileSizeMB:1000,r:true}" | ./mongoperf

       In this operation:

       • mongoperf tests direct physical random read io's, using 16 concurrent reader threads.

       • mongoperf  uses a 1 gigabyte test file.

       Consider using iostat, as invoked in the following example to monitor I/O performance during the test.

       iostat -xm 2

AUTHOR

       MongoDB Documentation Project

COPYRIGHT

       2011-2013, 10gen, Inc.

2.2.3                                            March 14, 2013                                     MONGOPERF(1)