LVM
Logical Volume Management on Linux
Links
- How do you clone an lvm partition?
- Monitoring with zabbix
- HOWTO
- Thin provisioning
- Beginner's guide to LVM
- Resizing LVM + DRBD
- http://wiki.tldp.org/LVM-on-RAID
- LVM nesting
- http://blog.gadi.cc/better-lvm-for-kvm/
- [https://www.tecmint.com/take-snapshot-of-logical-volume-and-restore-in-
- Taking a Backup Using Snapshots
- LVM mirrors
- https://www.thegeekdiary.com/how-to-convert-a-volume-to-stripe-raid0-volume-in-lvm/
- Get the most IOPS out of your physical volumes using LVM
NOTE: remember to add snapshot support when calling lvcreate
Raid on LVM
LVM Thin provisioning
Show some more about thin volumes
lvm -a
Related commands
lvs
lvdisplay
lvrename
lvrename groupname oldname newname
pvs
Show the pyhysical volumens
pvscan
pvresize
To use after chaning disk/partition size
vgrename
lsblk
partprobe
lvchange
vgchange
dmsetup
vgs
create physical volume
pvcreate /dev/sda3
lvcreate
lvcreate -L12G -nmyvol myvolumegroup lvcreate -l 100%FREE -nmyvol myvolumegroup
lvresize
Grow filesystem together with the volume
lvresize --resizefs -L+20G /dev/vg/foo
or grow to all remaining space vg:
lvresize -l +100%FREE /dev/myvg/myvol
lvremove
To remove all volumes in group VGname
lvremove VGname
To remove a volume
lvremove VGname/LVname
Do you really want to remove active logical volume
lvchange -a n vgname/lvname
just to make sure
Logical volume X/Y contains a filesystem in use
https://www.thegeekdiary.com/lvremove-command-fails-with-error-lvm-cant-remove-open-logical-volume/
Could be NFS. Always remember NFS! If NFS has indeed been involved, restarting nfs service will most likely fix this.
pvck
To find the metadata:
pvck /dev/sdb1
LVM snapshot
lvcreate --size 1G --snapshot --name snap-1 /dev/myvg/mylv
where size should be enough to hold the data changes
HOWTO
Extend striped volume
See here
Convert linear logical volume to striped
See here and here and here and here and this one seems most useful
Volume groups
Add disk to volume group
pvcreate /dev/sdc vgextend MYVG /dev/sdc
And if you need space right now:
lvextend -l +100%FREE /dev/NYVG/mylv
And then grow fs
Remove volume group
Deactivate the volume group:
vgchange -a n my_volume_group
Now you actually remove the volume group:
vgremove my_volume_group
Remove physical drive from a volume group
See here Make sure the data fits on remaining drives, then
pvmove /dev/sdbX vgreduce myvg /dev/sdbX
FAQ
Access logical volumes within logical volume
partprobe /dev/mapper/vg-mydata lsblk
This will show the (sub) partitions/volumes, then edit /etc/lvm/lvm.conf
filter = [ "a|.*/|", "a|mydata|","r|.*|" ]
Then run:
vgscan lvscan vgs
Now you should see the names of the volumes you're looking for, so now:
vgchange -a y guestsname_mydata-home
and then you should be able to
mount /dev/mapper/guestsname_mydata-home
When done, remember to change back the filter in lvm.conf, default is
filter = [ "a|.*/|" ]
and of course then once again
vgscan lvscan
vgreduce Can't remove final physical volume
Means you're trying to remove the last physical volume, instead just use
vgremove
grow logical volume
https://www.tldp.org/HOWTO/LVM-HOWTO/extendlv.html
lvextend -L+100G /dev/myvg/myvol
lvremove: Logical volume vg-kvm/vps-snapshot is used by another device.
Could be kpartx, see
/dev/mapper/
lvremove Logical volume foo/bar in use
check with lsof, fuser and:
losetup -l
to see if a /dev/dm-* looks familiar
some say lvchange -an the snapshot first, but that disables the lv it's connected to as well
OR
dmsetup info -c
http://blog.roberthallam.org/2017/12/solved-logical-volume-is-used-by-another-device/comment-page-1/
lvremove Do you really want to remove and DISCARD active logical volume
If you like, deactivate the volume first:
lvchange -an vgname/lvname
Grow physical volume
Assuming your LVM partition is the last one, use fdisk to delete and recreate it, remember to set type to LVM again and reboot. Then use pvresize /dev/sdaX
Or just:
pvresize /dev/sdb
vgreduce vgname /dev/sdbX
Create volume group
vgcreate vgname /dev/sdc1 /dev/sdd1
pvcreate Can't open /dev/sdg exclusively. Mounted filesystem?
pvcreate: Cannot use /dev/sdb: device is partitioned
some secret ritual required, or just create /dev/sdb1
Device /dev/sdb excluded by filter
Check disk label(gpt!!
Try:
wipefs -af /dev/sdg
WARNING: Device /dev/dm-17 not initialized in udev database even after waiting 10000000 microseconds.
Try
udevadm trigger
wipefs: error: /dev/sdg: probing initialization failed: Device or resource busy
try all ways to unbusy
Check if volume is in use
dmsetup info -c
Check the 'Open' column
WARNING: PV /dev/sda5 in VG foo-vg is using an old PV header, modify the VG to update.
vgck --updatemetadata foo-vg
Mount logical volume from disk image
See also https://backdrift.org/mounting-a-file-system-on-a-partition-inside-of-an-lvm-volume
kpartx -av /path/to.img lvscan mount /dev/mapper/what-ever-var /mnt/loop umount kpartx -d /path/to.img
Error reading device sdb
After pvremoving a disk:
wipefs -a /dev/sdb
pvmove: Cluster mirror log daemon is not running
Useless message, but if pvmove is failing: did you shrink your LV yet?
