On Fri, Aug 16, 2019 at 12:37 AM Nir Soffer <nsoffer@redhat.com> wrote: [snip]
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.
What kind of problems did you have? do we have a bug for this?
The problems I described in the referred thread of my previous answer: https://lists.ovirt.org/archives/list/users@ovirt.org/thread/S3LXEJV3V4CIOTQ... VM has been paused due to storage I/O problem Managing the vdsm related parameters: volume_utilization_percent and volume_utilization_chunk_mb mitigated the probability of occurrence but didn't solve definitely. I didn't open a bugzilla for that
So, as you did, I used preallocated for data based disks.
For best performance, we always recommended preallocated disks. I think you will get best results with direct LUN for applications that needs best performance.
And I did it, as you recommended, despite not optimized storage allocation, but solving the VM paused error. And this was also the reason why I didn't open a bugzilla, supposing the answer would have been to use preallocated and with thin provisioning not to be used in this use case scenario... Thanks, Gianluca