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authorLinus Torvalds <torvalds@linux-foundation.org>2010-03-06 22:34:04 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-06 22:34:04 +0300
commit87c7ae06cc50bcbcdcc60d64a959ca0b9b71f892 (patch)
tree14753708a10c8bf65517056cd3fc87a22a03eda9 /Documentation
parentdff6d1c5ef9116a4478908001d72ee67127ecf01 (diff)
parentf070304094edb8d516423e79edd27c97ec2020b0 (diff)
downloadlinux-87c7ae06cc50bcbcdcc60d64a959ca0b9b71f892.tar.xz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: dm raid1: fix deadlock when suspending failed device dm: eliminate some holes data structures dm ioctl: introduce flag indicating uevent was generated dm: free dm_io before bio_endio not after dm table: remove unused dm_get_device range parameters dm ioctl: only issue uevent on resume if state changed dm raid1: always return error if all legs fail dm mpath: refactor pg_init dm mpath: wait for pg_init completion when suspending dm mpath: hold io until all pg_inits completed dm mpath: avoid storing private suspended state dm: document when snapshot has finished merging dm table: remove dm_get from dm_table_get_md dm mpath: skip activate_path for failed paths dm mpath: pass struct pgpath to pg init done
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/device-mapper/snapshot.txt44
1 files changed, 44 insertions, 0 deletions
diff --git a/Documentation/device-mapper/snapshot.txt b/Documentation/device-mapper/snapshot.txt
index e3a77b215135..0d5bc46dc167 100644
--- a/Documentation/device-mapper/snapshot.txt
+++ b/Documentation/device-mapper/snapshot.txt
@@ -122,3 +122,47 @@ volumeGroup-base: 0 2097152 snapshot-merge 254:11 254:12 P 16
brw------- 1 root root 254, 11 29 ago 18:15 /dev/mapper/volumeGroup-base-real
brw------- 1 root root 254, 12 29 ago 18:16 /dev/mapper/volumeGroup-base-cow
brw------- 1 root root 254, 10 29 ago 18:16 /dev/mapper/volumeGroup-base
+
+
+How to determine when a merging is complete
+===========================================
+The snapshot-merge and snapshot status lines end with:
+ <sectors_allocated>/<total_sectors> <metadata_sectors>
+
+Both <sectors_allocated> and <total_sectors> include both data and metadata.
+During merging, the number of sectors allocated gets smaller and
+smaller. Merging has finished when the number of sectors holding data
+is zero, in other words <sectors_allocated> == <metadata_sectors>.
+
+Here is a practical example (using a hybrid of lvm and dmsetup commands):
+
+# lvs
+ LV VG Attr LSize Origin Snap% Move Log Copy% Convert
+ base volumeGroup owi-a- 4.00g
+ snap volumeGroup swi-a- 1.00g base 18.97
+
+# dmsetup status volumeGroup-snap
+0 8388608 snapshot 397896/2097152 1560
+ ^^^^ metadata sectors
+
+# lvconvert --merge -b volumeGroup/snap
+ Merging of volume snap started.
+
+# lvs volumeGroup/snap
+ LV VG Attr LSize Origin Snap% Move Log Copy% Convert
+ base volumeGroup Owi-a- 4.00g 17.23
+
+# dmsetup status volumeGroup-base
+0 8388608 snapshot-merge 281688/2097152 1104
+
+# dmsetup status volumeGroup-base
+0 8388608 snapshot-merge 180480/2097152 712
+
+# dmsetup status volumeGroup-base
+0 8388608 snapshot-merge 16/2097152 16
+
+Merging has finished.
+
+# lvs
+ LV VG Attr LSize Origin Snap% Move Log Copy% Convert
+ base volumeGroup owi-a- 4.00g