summaryrefslogtreecommitdiffstats
path: root/Documentation/device-mapper/dm-raid.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/device-mapper/dm-raid.txt')
-rw-r--r--Documentation/device-mapper/dm-raid.txt14
1 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt
index cd2cb2fc85ea..7e06e65586d4 100644
--- a/Documentation/device-mapper/dm-raid.txt
+++ b/Documentation/device-mapper/dm-raid.txt
@@ -170,6 +170,13 @@ The target is named "raid" and it accepts the following parameters:
Takeover/reshape is not possible with a raid4/5/6 journal device;
it has to be deconfigured before requesting these.
+ [journal_mode <mode>]
+ This option sets the caching mode on journaled raid4/5/6 raid sets
+ (see 'journal_dev <dev>' above) to 'writethrough' or 'writeback'.
+ If 'writeback' is selected the journal device has to be resilient
+ and must not suffer from the 'write hole' problem itself (e.g. use
+ raid1 or raid10) to avoid a single point of failure.
+
<#raid_devs>: The number of devices composing the array.
Each device consists of two entries. The first is the device
containing the metadata (if any); the second is the one containing the
@@ -254,7 +261,8 @@ recovery. Here is a fuller description of the individual fields:
<data_offset> The current data offset to the start of the user data on
each component device of a raid set (see the respective
raid parameter to support out-of-place reshaping).
- <journal_char> 'A' - active raid4/5/6 journal device.
+ <journal_char> 'A' - active write-through journal device.
+ 'a' - active write-back journal device.
'D' - dead journal device.
'-' - no journal device.
@@ -331,3 +339,7 @@ Version History
'D' on the status line. If '- -' is passed into the constructor, emit
'- -' on the table line and '-' as the status line health character.
1.10.0 Add support for raid4/5/6 journal device
+1.10.1 Fix data corruption on reshape request
+1.11.0 Fix table line argument order
+ (wrong raid10_copies/raid10_format sequence)
+1.11.1 Add raid4/5/6 journal write-back support via journal_mode option