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Diffstat (limited to 'Documentation/admin-guide/md.rst')
| -rw-r--r-- | Documentation/admin-guide/md.rst | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/Documentation/admin-guide/md.rst b/Documentation/admin-guide/md.rst index 1e61bf50595c..84de718f24a4 100644 --- a/Documentation/admin-guide/md.rst +++ b/Documentation/admin-guide/md.rst @@ -276,14 +276,14 @@ All md devices contain: array creation it will default to 0, though starting the array as ``clean`` will set it much larger. - new_dev + new_dev This file can be written but not read. The value written should be a block device number as major:minor. e.g. 8:0 This will cause that device to be attached to the array, if it is available. It will then appear at md/dev-XXX (depending on the name of the device) and further configuration is then possible. - safe_mode_delay + safe_mode_delay When an md array has seen no write requests for a certain period of time, it will be marked as ``clean``. When another write request arrives, the array is marked as ``dirty`` before the write @@ -292,7 +292,7 @@ All md devices contain: period as a number of seconds. The default is 200msec (0.200). Writing a value of 0 disables safemode. - array_state + array_state This file contains a single word which describes the current state of the array. In many cases, the state can be set by writing the word for the desired state, however some states @@ -401,7 +401,30 @@ All md devices contain: once the array becomes non-degraded, and this fact has been recorded in the metadata. + consistency_policy + This indicates how the array maintains consistency in case of unexpected + shutdown. It can be: + none + Array has no redundancy information, e.g. raid0, linear. + + resync + Full resync is performed and all redundancy is regenerated when the + array is started after unclean shutdown. + + bitmap + Resync assisted by a write-intent bitmap. + + journal + For raid4/5/6, journal device is used to log transactions and replay + after unclean shutdown. + + ppl + For raid5 only, Partial Parity Log is used to close the write hole and + eliminate resync. + + The accepted values when writing to this file are ``ppl`` and ``resync``, + used to enable and disable PPL. As component devices are added to an md array, they appear in the ``md`` @@ -563,6 +586,9 @@ Each directory contains: adds bad blocks without acknowledging them. This is largely for testing. + ppl_sector, ppl_size + Location and size (in sectors) of the space used for Partial Parity Log + on this device. An active md device will also contain an entry for each active device |