diff options
Diffstat (limited to 'Documentation/admin-guide/device-mapper/writecache.rst')
| -rw-r--r-- | Documentation/admin-guide/device-mapper/writecache.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/writecache.rst b/Documentation/admin-guide/device-mapper/writecache.rst index dce0184e07ca..c181f26af769 100644 --- a/Documentation/admin-guide/device-mapper/writecache.rst +++ b/Documentation/admin-guide/device-mapper/writecache.rst @@ -53,6 +53,21 @@ Constructor parameters: - some underlying devices perform better with fua, some with nofua. The user should test it + cleaner + when this option is activated (either in the constructor + arguments or by a message), the cache will not promote + new writes (however, writes to already cached blocks are + promoted, to avoid data corruption due to misordered + writes) and it will gradually writeback any cached + data. The userspace can then monitor the cleaning + process with "dmsetup status". When the number of cached + blocks drops to zero, userspace can unload the + dm-writecache target and replace it with dm-linear or + other targets. + max_age n + specifies the maximum age of a block in milliseconds. If + a block is stored in the cache for too long, it will be + written to the underlying device and cleaned up. Status: 1. error indicator - 0 if there was no error, otherwise error number @@ -77,3 +92,5 @@ Messages: 5. resume the device, so that it will use the linear target 6. the cache device is now inactive and it can be deleted + cleaner + See above "cleaner" constructor documentation. |