How to determine when a snapshot merging is complete ?
Red Hat Enterprise Linux
- LVM snapshot still appears after executing lvconvert with merge command and server reboot
- Unable to identify status of LVM snapshot merge status
- 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
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