At the beginning, it look like:
~# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
log system -wi-ao---- 1.86g
root system -wi-ao---- 2.79g
swap system -wi-ao---- 1.86g
tmp system -wi-ao---- 1.86g
usr system -wi-ao---- 1.86g
var system -wi-ao---- 31.72g
testlv systemtest -wi------- 5.00g
testlv2 systemtest -wi------- 20.00g
~# pvs
PV VG Fmt Attr PSize PFree
/dev/md0 systemtest lvm2 a-- 884.63g 859.63g
/dev/sdk3 system lvm2 a-- 147.61g 105.66g
Now we begin to merge the two volume groups to one.
vgsplit -n systemtest/testlv systemtest system
Now it look like:
~# pvs
PV VG Fmt Attr PSize PFree
/dev/md0 system lvm2 a-- 884.63g 859.63g
/dev/sdk3 system lvm2 a-- 147.61g 105.66g
~# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
log system -wi-ao---- 1.86g
root system -wi-ao---- 2.79g
swap system -wi-ao---- 1.86g
tmp system -wi-ao---- 1.86g
usr system -wi-ao---- 1.86g
var system -wi-ao---- 31.72g
testlv system -wi------- 5.00g
testlv2 system -wi------- 20.00g
Now we want to remove md0, but before we must move the data to the other physical volume.
~# pvmove /dev/md0
/dev/md0: Moved: 0.0%
/dev/md0: Moved: 5.5%
/dev/md0: Moved: 10.6%
/dev/md0: Moved: 14.1%
/dev/md0: Moved: 17.6%
/dev/md0: Moved: 21.8%
/dev/md0: Moved: 25.3%
/dev/md0: Moved: 28.9%
/dev/md0: Moved: 32.4%
/dev/md0: Moved: 36.2%
/dev/md0: Moved: 39.8%
/dev/md0: Moved: 43.6%
/dev/md0: Moved: 47.4%
/dev/md0: Moved: 50.7%
/dev/md0: Moved: 54.6%
/dev/md0: Moved: 58.1%
/dev/md0: Moved: 62.0%
/dev/md0: Moved: 65.9%
/dev/md0: Moved: 69.1%
/dev/md0: Moved: 72.9%
/dev/md0: Moved: 76.9%
/dev/md0: Moved: 80.0%
/dev/md0: Moved: 83.7%
/dev/md0: Moved: 87.2%
/dev/md0: Moved: 90.8%
/dev/md0: Moved: 95.0%
/dev/md0: Moved: 98.6%
/dev/md0: Moved: 100.0%
Now we can remove the md0 from the system volume group.
~# vgreduce system /dev/md0
Removed "/dev/md0" from volume group "system"