NAME

       pmempool-feature - toggle or query pool set features

SYNOPSIS

              $ pmempool feature (-e|-d|-q feature-name) [options] <file>

DESCRIPTION

       The pmempool feature command enables / disables or queries pool set features.

       Available pool feature-names are:

       • SINGLEHDR  -  only  the  first  part  in  each  replica  contains the pool part internal
         metadata.  This value can be used only with -q.  It can not be enabled or disabled.  For
         details see poolset(5).

       • CHECKSUM_2K  - only the first 2KiB of pool part internal metadata is checksummed.  Other
         features may depend on this one to store additional metadata in otherwise unused  second
         2KiB part of a header.  When CHECKSUM_2K is disabled whole 4KiB is checksummed.

       • SHUTDOWN_STATE - enables additional check performed during pool open which verifies pool
         consistency in the presence of dirty shutdown.  CHECKSUM_2K has to be enabled  prior  to
         SHUTDOWN_STATE otherwise enabling SHUTDOWN_STATE will fail.

       • CHECK_BAD_BLOCKS  -  enables  checking  bad  blocks  performed during opening a pool and
         fixing bad blocks performed by pmempool-sync during syncing a  pool.   Currently  (Linux
         kernel  v4.19,  libndctl  v62) checking and fixing bad blocks require read access to the
         following resource files (containing physical addresses) of NVDIMM  devices  which  only
         root can read by default:

         /sys/bus/nd/devices/ndbus*/region*/resource
         /sys/bus/nd/devices/ndbus*/region*/dax*/resource
         /sys/bus/nd/devices/ndbus*/region*/pfn*/resource
         /sys/bus/nd/devices/ndbus*/region*/namespace*/resource

       It is possible to use poolset as file argument.  But poolsets with remote replicas are not
       supported.

   Available options:
       -h, --help

       Print help message.

       -v, --verbose

       Increase verbosity level.

       -e, --enable feature-name

       Enable feature for pool set.

       -d, --disable feature-name

       Disable feature for pool set.

       -q, --query feature-name

       Print feature status.

COMPATIBILITY

       Poolsets with features not defined in this document (e.g. enabled by  the  newer  software
       version) are not supported.

DISCLAIMER

       pmempool feature command is not fail safe.

EXAMPLE

              $ pmempool feature --enable CHECKSUM_2K pool.set

       Enables POOL_FEAT_CKSUM_2K incompat feature flag.

              $ pmempool feature --disable CHECKSUM_2K pool.set

       Disables POOL_FEAT_CKSUM_2K incompat feature flag.

              $ pmempool feature --query CHECKSUM_2K pool.set
              0

       Prints POOL_FEAT_CKSUM_2K incompat feature flag value.

SEE ALSO

       poolset(5) and <https://pmem.io>