1PMEMPOOL-FEATURE(1)        PMDK Programmer's Manual        PMEMPOOL-FEATURE(1)
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NAME

6       pmempool-feature - toggle or query pool set features
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SYNOPSIS

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

12       The  pmempool  feature  command  enables / disables or queries pool set
13       features.
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15       Available pool feature-names are:
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17       • SINGLEHDR - only the first part in each  replica  contains  the  pool
18         part internal metadata.  This value can be used only with -q.  It can
19         not be enabled or disabled.  For details see poolset(5).
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21       • CHECKSUM_2K - only the first 2KiB of pool part internal  metadata  is
22         checksummed.   Other  features  may depend on this one to store addi‐
23         tional metadata in otherwise unused second 2KiB  part  of  a  header.
24         When CHECKSUM_2K is disabled whole 4KiB is checksummed.
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26       • SHUTDOWN_STATE  - enables additional check performed during pool open
27         which verifies pool consistency in the presence  of  dirty  shutdown.
28         CHECKSUM_2K  has  to be enabled prior to SHUTDOWN_STATE otherwise en‐
29         abling SHUTDOWN_STATE will fail.
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31       • CHECK_BAD_BLOCKS - enables checking bad blocks performed during open‐
32         ing  a  pool  and fixing bad blocks performed by pmempool-sync during
33         syncing a pool.  Currently (Linux kernel v4.19, libndctl v62)  check‐
34         ing  and  fixing  bad blocks require read access to the following re‐
35         source files (containing physical addresses) of NVDIMM devices  which
36         only root can read by default:
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38         /sys/bus/nd/devices/ndbus*/region*/resource
39         /sys/bus/nd/devices/ndbus*/region*/dax*/resource
40         /sys/bus/nd/devices/ndbus*/region*/pfn*/resource
41         /sys/bus/nd/devices/ndbus*/region*/namespace*/resource
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43       It  is possible to use poolset as file argument.  But poolsets with re‐
44       mote replicas are not supported.
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46   Available options:
47       -h, --help
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49       Print help message.
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51       -v, --verbose
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53       Increase verbosity level.
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55       -e, --enable feature-name
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57       Enable feature for pool set.
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59       -d, --disable feature-name
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61       Disable feature for pool set.
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63       -q, --query feature-name
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65       Print feature status.
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COMPATIBILITY

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

72       pmempool feature command is not fail safe.
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EXAMPLE

75              $ pmempool feature --enable CHECKSUM_2K pool.set
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77       Enables POOL_FEAT_CKSUM_2K incompat feature flag.
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79              $ pmempool feature --disable CHECKSUM_2K pool.set
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81       Disables POOL_FEAT_CKSUM_2K incompat feature flag.
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83              $ pmempool feature --query CHECKSUM_2K pool.set
84              0
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86       Prints POOL_FEAT_CKSUM_2K incompat feature flag value.
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SEE ALSO

89       poolset(5) and <https://pmem.io>
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93PMDK - pmem Tools version 1.4     2021-07-22               PMEMPOOL-FEATURE(1)
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