On Thu, Aug 15, 2019 at 10:35 AM Evelina Shames <eshames(a)redhat.com> wrote:
Hey Kevin,
By design, when creating a snapshot, the new volume is created with
'sparse' allocation policy.
I suggest you to open a bug since this operation should not crash the VM.
Add this description and please add all relevant logs and any relevant
information of your environment.
Regards,
Evelina
On Tue, Aug 13, 2019 at 4:10 PM Kevin Doyle <kevin.doyle(a)manchester.ac.uk>
wrote:
> Hi I have linux VM with 2 disks one for OS is sparse the other is for a
> Database and is Preallocated. When I take a snapshot of the VM both disks
> change to sparse policy but the disks in the snapshot are 1 sparse and 1
> allocated. Before the snapshot the VM was running fine, now it crashes when
> data is written to the database. When I delete the snapshot the disks go
> back to 1 sparse and 1 allocated. Has anyone else seen this happen. Ovirt
> is 4.3.2.1-1.el7 and it is running on a hostedEngine
>
> Many thanks
> Kevin
> _______________________________________________
>
Hi,
some clarifications needed: what kind of storage are you using?
If block based (iSCSI or FC-SAN) I verified problems on sparse allocated
disks and databases (Oracle in my case) during high I/O on datafiles.
So, as you did, I used preallocated for data based disks.
For fine tuning of automatic LVM extensions in case of block based storage
domains, see also this 2017 thread:
https://lists.ovirt.org/archives/list/users@ovirt.org/thread/S3LXEJV3V4CI...
not currently using it tohugh with recent versions of oVirt, so I have no
"fresh" information about efficiency, depending on I/O load amount
HIH anyway,
Gianluca