Friday, February 15

Tag: lvm

LVM: “Unable to create a snapshot smaller than 2 chunks”

Craig's PlanetPostgreSQL
If you try to create an LVM snapshot with lvm lvcreate -s -n snapname -L 100G myvg and it fails with Unable to create a snapshot smaller than 2 chunks. ... it's probably actually trying to tell you "I don't have 100GB free on this VG, allocate a smaller snapshot". It's choosing to phrase it creatively. You'll only get this error if you're within a certain margin of sizes: much too big and it'll tell you a rather clearer: Volume group "myvg" has insufficient free space (1000 extents): 2000 required. so it's really just a bit of a limitation or cosmetic bug. It's not very Google-able though, hence this post. Next time I hit this error I'll search for it and find my own writing, having completely forgotten that I was involved in a case where the team I was on saw (more…)