“A friend answered me: the last snapshot is required to take any future
snapshots, that is the reason it stays on primary store”
That answer is correct as far as I know. If you take another volume snapshot,
we only want to transfer the data since the prior volume snapshot. To do this,
we need to keep the most recent VM snapshot on primary. Aside from when the VM
snapshot’s data is actually being copied to secondary storage, I think you
should only see one VM snapshot on primary at a time.
It should look like this:
SR:
Volume VDI
You take a volume snapshot.
SR:
Snapshot VDI
Volume VDI
You take another volume snapshot.
During the copy process:
SR:
Snapshot VDI (new)
Snapshot VDI (original)
Volume VDI
After the copy process the original Snapshot VDI should be merged into the new
Snapshot VDI:
SR:
Snapshot VDI (new)
Volume VDI
Note that it’s actually a bit more complicated than this: When you take a VM
snapshot using XenServer, you get a new read-only VDI and a new read/write VDI
for future writes, but the idea above should be approximately accurate.
On 6/6/17, 8:04 AM, "Lotic Lists" <li...@lotic.com.br> wrote:
Hi team
I have a doubt, why ACS allocate primary storage for latest snapshot VDI of
a volume?
The snapshot was transferred to secondary storage but continued on primary.
This is a problem because it uses space of SR (XenServer).
Physical space of snapshot is not a problem, the VDI have 211K on primary
storage, but virtual space have original size of volume.
It's a waste of space, especially when storage is space-licensed
A friend answered me: the last snapshot is required to take any future
snapshots, that is the reason it stays on primary store
How community see that?
Regards.
Marcelo
