summaryrefslogtreecommitdiff
path: root/Documentation/admin-guide/md.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/admin-guide/md.rst')
-rw-r--r--Documentation/admin-guide/md.rst32
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