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
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:
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