how to snapshot thin provisioned lvm I'm trying to create an snapshot from a thin provisioned lvm using the below command, but i get errors, is there anyone that can help me? root@ghv214:/dev/ghv214-vg# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert Thin_LVM ghv214-vg twi-a-tz-- 10.00g 0.00 10.35 kvm_pool ghv214-vg -wi-ao---- 2.69t root ghv214-vg -wi-ao---- 59.60g swap ghv214-vg -wi-ao---- 29.80g var ghv214-vg -wi-ao---- 29.80g Command to create snapshot: root@ghv214:/dev/ghv214-vg# lvcreate -s -n snap_test ghv214-vg/Thin_LVM Please specify either size or extents with snapshots. but I can create snapshot from non-thin provisioned lvms.

`ghv214-vg/Thin_LVM` is a thin pool (the lower `t` attribute stands for thin pool), not a thin LV so you are trying to create a "normal" snapshot of a thin pool which requires size to be specified. In general it doesn't really make sense to create snapshot of the thin pool, you want to snapshot the thin LVs. But you actually don't have a thinly provisioned LV in your system, when creating a thin pool you can create the thin pool and a thin LV on it with one command:


lvcreate --type thin -V VirtualSize -L LargeSize -n ThinLV --thinpool VG/ThinPoolLV


but if you are doing it separately (creating the pool first) you need to create the thin LV later with


lvcreate -n ThinLV -V VirtualSize --thinpool VG/ThinPoolLV


and then you can create the snapshot of the thin LV with


lvcreate -n SnapLV --snapshot VG/ThinLV


See lvmthin man page for more information.