Provided by: zfs-test_0.7.9-3ubuntu6_amd64 bug


       ztest - was written by the ZFS Developers as a ZFS unit test.


       ztest <options>


       This manual page documents briefly the ztest command.

       ztest  was  written  by  the  ZFS Developers as a ZFS unit test. The tool was developed in
       tandem with the ZFS functionality and was executed nightly as one of the  many  regression
       test against the daily build. As features were added to ZFS, unit tests were also added to
       ztest.  In addition, a separate test development team wrote and executed  more  functional
       and stress tests.

       By  default  ztest  runs  for  ten minutes and uses block files (stored in /tmp) to create
       pools rather than using physical disks.  Block files afford ztest its flexibility to  play
       around  with  zpool  components without requiring large hardware configurations.  However,
       storing the block files in /tmp may not work for you if you have a small tmp directory.

       By default is non-verbose. This is why entering the command above  will  result  in  ztest
       quietly  executing  for  5 minutes. The -V option can be used to increase the verbosity of
       the tool. Adding multiple -V option is allowed and the more you add the more chatty  ztest

       After  the  ztest  run completes, you should notice many ztest.*  files lying around. Once
       the run completes you can safely remove these files. Note that you shouldn't remove  these
       files  during  a  run.  You  can re-use these files in your next ztest run by using the -E



              Print a help summary.

       -v vdevs (default: 5)

              Number of vdevs.

       -s size_of_each_vdev (default: 64M)

              Size of each vdev.

       -a alignment_shift (default: 9) (use 0 for random)

              Used alignment in test.

       -m mirror_copies (default: 2)

              Number of mirror copies.

       -r raidz_disks (default: 4)

              Number of raidz disks.

       -R raidz_parity (default: 1)

              Raidz parity.

       -d datasets (default: 7)

              Number of datasets.

       -t threads (default: 23)

              Number of threads.

       -g gang_block_threshold (default: 32K)

              Gang block threshold.

       -i initialize_pool_i_times (default: 1)

              Number of pool initialisations.

       -k kill_percentage (default: 70%)

              Kill percentage.

       -p pool_name (default: ztest)

              Pool name.


              Verbose (use multiple times for ever more blather).


              Use existing pool (use existing pool instead of creating new one).

       -T time (default: 300 sec)

              Total test run time.

       -z zil_failure_rate (default: fail every 2^5 allocs)

              Injected failure rate.


       To override /tmp as your location for block files, you can use the -f option:

              ztest -f /

       To get an idea of what ztest is actually testing try this:

              ztest -f / -VVV

       Maybe you'd like to run ztest for longer? To do so simply use the -T  option  and  specify
       the runlength in seconds like so:

              ztest -f / -V -T 120


              Use  id  instead  of  the  SPL hostid to identify this host.  Intended for use with
              ztest, but this environment variable will affect any utility which  uses  libzpool,
              including  zpool(8).   Since  the  kernel  is  unaware of this setting results with
              utilities other than ztest are undefined.

              Limit the default stack size to stacksize bytes for the purpose  of  detecting  and
              debugging  kernel  stack overflows.  This value defaults to 32K which is double the
              default 16K Linux kernel stack size.

              In practice, setting the stack size slightly higher is needed  because  differences
              in  stack  usage between kernel and user space can lead to spurious stack overflows
              (especially when debugging is enabled).  The specified value will be rounded up  to
              a  floor  of  PTHREAD_STACK_MIN  which  is  the  minimum  stack required for a NULL
              procedure in user space.

              By default the stack size is limited to 256K.


       spl-module-parameters (5), zpool (1), zfs (1), zdb (1),


       This manual page was transvered to asciidoc by Michael Gebetsroither <>  from