LVM, LVM Thin vs qcow2
- Thread starter melanch0lia
- Start date
The order you provided is the order of decreasing performance: LVM, LVM Thin, QCOW2
You have to figure out what features you want to use. QCOW2 has a lot of features (snapshots, snapshots of RAM, etc.) but it is or course the slowest. If you want to have best performance, then use thick LVM volumes.
You have to figure out what features you want to use. QCOW2 has a lot of features (snapshots, snapshots of RAM, etc.) but it is or course the slowest. If you want to have best performance, then use thick LVM volumes.
You cannot: Snapshots are no backups!
Technically, all provide snapshots, but the 'feature-richest' is QCOW2. You can create "real" snapshots of live machines (including RAM), go back-and-forth in time, e.g. It's the best for that, therefore also the slowest.
And please do real backups! Using the backup-tools of Proxmox (or synching the files manually e.g. zfs send/receive for ZFS, everything else will be toooo slow).
Technically, all provide snapshots, but the 'feature-richest' is QCOW2. You can create "real" snapshots of live machines (including RAM), go back-and-forth in time, e.g. It's the best for that, therefore also the slowest.
And please do real backups! Using the backup-tools of Proxmox (or synching the files manually e.g. zfs send/receive for ZFS, everything else will be toooo slow).
Not sure we're on the same page but https://pve.proxmox.com/wiki/Backup_and_Restore#Backup => There are 3 backup modes available:
I'm interested in the called "snapshot"
Oh yeah, I misunderstood your question. I cannot say which is better, because this is a more or less boolean question.On KVM there is no problem because QEMU handles the time-consistent snapshot of the disk drive with or without storage backend snapshot availability.
On LXC I'm not sure, but all storage types LVM, LVM-thin, QCOW2 (and also ZFS, Ceph, etc.) do have snapshot capability, so they can be used (technically speaking). I do not know how they're used internally in PVE. Maybe someone from Proxmox could comment on that.
On LXC I'm not sure, but all storage types LVM, LVM-thin, QCOW2 (and also ZFS, Ceph, etc.) do have snapshot capability, so they can be used (technically speaking). I do not know how they're used internally in PVE. Maybe someone from Proxmox could comment on that.
The snapshot mode backup for containers works like this:
the snapshot-mechanism is just a means to achieve very short downtime (only the time it takes to snapshot all volumes), the resulting backup is not related to any snapshots at all. in fact, modulo some variations regarding duplicate directory entries from and sort order of mountpoints, all three modes produce archives with the same content.
the suspend mode backup uses a similar trick to achieve little downtime (but usually longer than snapshot):
Code:
create 'vzdump' snapshot of container:
- sync and freeze container if running
- create snapshots of all volume mountpoints
- unfreeze container if running
mount 'vzdump' snapshot
create backup from mounted snapshot
unmount 'vzdump' snapshot
delete 'vzdump' snapshotthe snapshot-mechanism is just a means to achieve very short downtime (only the time it takes to snapshot all volumes), the resulting backup is not related to any snapshots at all. in fact, modulo some variations regarding duplicate directory entries from and sort order of mountpoints, all three modes produce archives with the same content.
the suspend mode backup uses a similar trick to achieve little downtime (but usually longer than snapshot):
Code:
copy files to temp directory while running
freeze container
copy delta to temp directory while frozen
unfreeze container
create backup from temp directory