nareshunik
Enthusiast
Enthusiast

when i create a snapshot for VM with virtual disk of 20TB, how much space will it occupy

I have a vm with thick disk used space of 20TB DFS server and it's configured in thick disk. i have made changes in .vmx to move the snapshot to different datastore.

I need to know how much space will it consume for the initial snapshot.

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a_p_
Leadership
Leadership

The initial snapshot will start with only a few MB in size (depends on whether the VM is powered on or off as well as the data change rate in the guest OS). However, it can grow up to the provisioned size of the virtual disk.

When creating snapshots in another location, keep in mind that virtual disks with snapshots are used as a chain, where the latest chain link is used for R/W and the others are used for Read-Only. Placing a snapshot on a slower tier will impact the VM's performance.

André

nareshunik
Enthusiast
Enthusiast

Thanks.

We are using HITACHI solution to backup via snapshot. The data growth will be max 20GB and planning to have a dedicated datastore of 5TB for snapshot.

will the solution work? the snapshot will be for 12hours

a_p_
Leadership
Leadership

I don't think you will have issues with the disk space. Is there a special reason why you want/need to locate snapshots on another datastore, i.e. making things more complex? (see http://kb.vmware.com/kb/1015180)

André

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nareshunik
Enthusiast
Enthusiast

Because in the current datastore there is no free space, we have only 200GB free space left on each datastore. That's why we are moving the snapshot to different datastore.

We are planning to move the snapshot in Tier-1 datastore. will there be any issues in moving to different datastore

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a_p_
Leadership
Leadership

With moving the snapshots to a same (or higher) tier storage/LUN you shouldn't have issues. I just wanted to make you aware of possible performance issues. Anyway, isn't there a chance to simply increase the size of the existing datastore instead of creating another one?

André

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nareshunik
Enthusiast
Enthusiast

I can increase the datastore by adding another LUN, in case of any of the one lun goes issue the entire datatore will have issues.

Thats why i am planning to go for another datastore for snapshot.

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a_p_
Leadership
Leadership

I agree that rather to increasing the datastore by adding extents, it may be better to relocate the snapshots.

Just for me to understand this, isn't it possible to increase the existing LUN by 5TB on the storage system?

André

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