restore point as snapshot - forever

[ricky73]

What problems can I have if I have 2-3 snapshot (to keep alive forever)  for a vm which is working?

What solution can I follow if I wish to keep "some snapshot" to use as restore points?

I now snapshot creates performance and disk space use issues.

[Nick_Andreev]

Snapshots can cause significant performance degradation if kept for too long. If that's not an issue in your case, you can keep them for however long you want, as long as you have enough storage on the datastore.

When protecting VMs, however, I would still recommend to implement a proper backup solution. Snapshots are not a backup, as they are kept on the same media as the original data they are created from.

[TheBobkin]

Hello Ricky,

Just a quick bit of info on how snapshots work in vSphere:

- When you snapshot a VM, it creates a new snapshot disk attached to each of the VMs vmdk disks.

- Any Write IOs to this VM are written to the snapshots, not the original base-disks (thus the base vmdk disks remain in the state they were when the snapshot was taken) - this means the snapshots grow in size over time and if left long enough or enough writes are made they will eventually equal the size of the original base-disks which is terribly wasteful of storage space.

- Multiple snapshots on a vmdk will degradate the performance of the VM as these are configured in a chain and reads may need to be done against multiple 'disks' in the chain instead of just a single disk (as it would if there were no snapshots).

- Snapshots are intended for short-term use only e.g. while taking back-ups or taken before making changes to a VM that may result in issues (so that these changes can be backed out of quickly by reverting to the state before the snapshot was taken).

kb.vmware.com/kb/1025279

So in short - don't use snapshots as a form of back-up, these are not intended nor do they function in this manner, if you want point-in-time states of a VM over a long time period then take full back-ups of these VMs and then some form of incremental/differential back-ups at later dates.

Bob

[ricky73]

I read VMware article you suggested and I understand what issues I can get.

If I have test machine where there are few changes, only sometimes occurs come user use it , it's for experimental environment... what do you think?

What free software can I use to save some server states to restore at necessity? E.g. equivalent to 3 snapshots: clean Windows 2012 server installation, Oracle installation, patch installation.

[a_p_]

Snapshots are fine for test environments like you describe it.

Please keep in mind that VM based backup applications usually don't backup snapshots, so you may loose them in case you need to restore the VM from backup.

Other than using snapshots, you could backup the VM at certain points in time, or export it to OVF/OVA to be able to restore it to a desired state.

What you are going to use in the end depends on the requirements.

André

[ricky73]

Infact I'm going to backup the VM at certain points in time (corresponding to snapshot time).

About OVA/OVF I think this format doesn't keep snapshots, right? Otherwise you would tell me!

OVA/OVF takes much space? It's compressed ? Or equivalent to hard disk size and memory size?

[a_p_]

About OVA/OVF I think this format doesn't keep snapshots, right? Otherwise you would tell me!

Unfortunately, none of the options (backup/restore or export/import) will maintain snapshots.

OVA/OVF takes much space? It's compressed ? Or equivalent to hard disk size and memory size?

OVF exports - besides some metadata - the guest's used disk space. OVA is an archive which contains all of the OVF files in a compressed format (comparable to a .zip archive).

André

[ricky73]

What reason (if there is one) could it cause to lost all snapshot of all vm or single vm? E.g. update job of VMware infrastructure.

My intention is to discourage to create snapshots!