Backup vs Snapshot

vikozo

Renowned Member
May 4, 2014
781
30
93
suisse
www.wombat.ch
hello
on a running KVM Server, i have the option to do a Backup or the Snapshot!
What is the difference? in which situation it is better to use which?

have a nice day
vinc
 
Hi,
Backups are independent from your vm and can be stored everywhere like every file.
Snapshots are in or on your vm-disk so you cant take it away.

Backups are full copy's of the vm and need more space
snapshots need less storage.

Backups take time snapshots are instant.
 
  • Like
Reactions: paxmobile
I think the reason why questions like these arise is that http://pve.proxmox.com/wiki/Backup_and_Restore also talks about snapshot backups :)
I admit it took me a while to figure out the differences...
[h=2]Backup[/h]There are 3 backup modes available:

  • stop (KVM): Shutdown the VM to get a consistent state, Then start KVM live backup and restart the VM (short downtime).
  • stop (OpenVZ and LXC): Stop the VM/CT during backup (very long downtime)
  • suspend (KVM): same behaviour as 'snapshot' mode.
  • suspend (OpenVZ and LXC): Use suspend/resume and multiple rsync passes. You can backup with minimal downtime without using LVM.
  • snapshot (KVM): Use KVM live backup (no downtime, online)
  • snapshot (OpenVZ): Use LVM2 snapshots (no downtime, online)
  • snapshot (LXC): Use storage snapshots, as long as the storage support this, for example ZFS or Ceph (no downtime, online)
 
backup use external stoarge..
how about snapshot? will eat vm storage it self?
 
The snapshots will always consume space of storage your VM is stored on. When doing a snapshot, that should also include the RAM of the VM, then that additional RAM dump will be stored on the storage you can define in the VMs options menu at "VM State Storage". This will by default be the storage of your VM.
 
Last edited:
vm state storage: automatic
it means will eat VM storage itself?

can u give me the example when we need to choose "include ram" and when we do not need "include ram" during snapshot. thanks
 
vm state storage: automatic
it means will eat VM storage itself?
Yes.
can u give me the example when we need to choose "include ram" and when we do not need "include ram" during snapshot. thanks
Restoring a snapshot without "include RAM" is like restoring a VM that crashed because of a power outage/hard reset. Restoring a VM with "include RAM" will restore a running VM that is exactly in the state it was when you snapshotted it (all your VMs processes will still be running and so on).
 
Last edited:

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!