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Snapshot when backing up VMs in VMware

Level 5


We are using BE201 R2 with AVVI agent. When starting a back up the status says creating snapshot.

How much space will the snapshot take when backing up a VM with AVVI, and where will it be stored?

We have a couple of stores witch only 50GB space left and the VMs in it are up to 300 GB



Level 6
Partner Accredited

The snapshot will not take any space.

Only the diskspace changed during the backup will be used.


If you make backup during non-officehours there won't be much changes, so the snapshots will stay very small.

Level 6
Partner Accredited

I think it is better to configure separate jobs for each VM as you are using snapshots. 

If you are having all VM's with a same job, the cache may not be cleared after backing a single VM.

Same was my experience with other software.

Level 6
Partner Accredited

I can say that I do not have problems with putting all VM's in one single job. The snapshots are created for one server, then a backup of the server is created and after that the snapshot is removed and the process continues to the next server.

You can imagine that is is not nice when you have more than 30 to 40 VM's you have to create a job for each server.

Level 6
Employee Accredited Certified

Dont worry about space. When you create a snapshot, all that happens is any new activity on VM goes to a different disk instead of the original one. So, no difference in terms of space, as VM would any ways have disk activity and data would have gone somewhere. There may be some space used for carryint out consolidation, but that is negligible. Regarding your question on where is the snapshot stored.. it is stored in the same location where your VM disks are located.

Please mark it a solution, if this post is useful.


Employee Accredited Certified

One extra comment - Backup Exec requests that ESX does the snapshot so if you want more detailed information you probably need to be looking at VMware knowledgebase (or forums)

Level 6
Partner Accredited


Snapshots are usualy created on the datastore where the .vmx reside.
As stated size "consumed" depend on changes made by the runing VM to its disks.
(you can see them, browsing you datastore or through the storage view > view all VM disks.)

Corresponding space will be released when snapshot is commited (understand deleted).

For the RDM vmdk created with "virtual compatibility", for those, as far as I remember, snapshots are ALSO created on the datastore along with the .vmx configuration file.
If you have heavy load on that VM an expect high disks performance thanks to RDM, you should be carreful as performance could be impacted (if datastore disks are slow: let say 10000rpm compare to 15000rpm one you could have on your RDM hardware storage system.