Hi Wesley,

Currently, there is no direct way to change disks allocation policy (thin-provision <-> preallocation).

In your case, it sounds like your ISCSI storage is running out of space, changing disk from thin-provisioned to preallocation will consume more space on the storage, thin-provision is more space effective but impact the performance.

On Mon, Apr 15, 2019 at 8:35 PM Wesley Stewart <wstewart3@gmail.com> wrote:

I am currently running a ZFS server (Running RaidZ2) and I have been experimenting with NFS and shares to host my guests. I am currently running oVirt 4.2.8 and using a RaidZ2 NFS mount for the guests.

ZFS definitely is definitely pretty awful (At least in my experience so far) for hosting VMs. I believe this is due to the synchronous writes being performed. However, I think running an iSCSI target with Synchronization disabled over a 10Gb connection might do the trick. (I have a couple of mirroed SSD drives for performance if I need it, but the RaidZ2 crawls for disk speed).

When I tried to migrate a thin provisioned guest to iSCSI, I keep getting an "Out of disk space error" which I am pretty sure is due to the block style storage on the iSCSI target. Is there a way to switch from Thin to Preallocated? Or is my best bet to try and take a snapshot and clone this into a pre-allocated disk?
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Regards,

Eyal Shenitzky

On Mon, Apr 15, 2019 at 8:35 PM Wesley Stewart <wstewart3@gmail.com> wrote:

I am currently running a ZFS server (Running RaidZ2) and I have been experimenting with NFS and shares to host my guests. I am currently running oVirt 4.2.8 and using a RaidZ2 NFS mount for the guests.

ZFS definitely is definitely pretty awful (At least in my experience so far) for hosting VMs. I believe this is due to the synchronous writes being performed. However, I think running an iSCSI target with Synchronization disabled over a 10Gb connection might do the trick. (I have a couple of mirroed SSD drives for performance if I need it, but the RaidZ2 crawls for disk speed).

When I tried to migrate a thin provisioned guest to iSCSI, I keep getting an "Out of disk space error" which I am pretty sure is due to the block style storage on the iSCSI target. Is there a way to switch from Thin to Preallocated? Or is my best bet to try and take a snapshot and clone this into a pre-allocated disk?
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Privacy Statement: https://www.ovirt.org/site/privacy-policy/
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List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/SZDBAGS6Y66SJATBCVDNSLWYTOYIXHJR/