LVM

Logical Volume Management on Linux

Link

• 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

NOTE: remember to add snapshot support when calling lvcreate

Related commands

create physical volume

pvcreate /dev/sda3

lvcreate

lvcreate -L12G -nmyvol myvolumegroup
lvcreate -l 100%FREE -nmyvol myvolumegroup

lvresize

lvresize --resizefs -L-2G /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

pvck

To find the metadata:

pvck /dev/sdb1

LVM snapshot

• https://www.tecmint.com/take-snapshot-of-logical-volume-and-restore-in-

lvcreate --size 1G --snapshot --name snap-1 /dev/myvg/mylv

where size should be enough to hold the data changes

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

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

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

• http://naveen161089.blogspot.nl/2014/03/forcefully-remove-lvm.html

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/

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

Remove physical drive from a volume group

Make sure the data fits on remaining drive, then

pvmove /dev/sdbX
vgreduce /dev/sdbX

Create volume group

vgcreate vgname /dev/sdc1 /dev/sdd1

Device /dev/sdb excluded by filter

Try:

 wipefs -af /dev/sdb