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 <[email protected]> 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?
> _______________________________________________
> Users mailing list -- [email protected]
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>


-- 
Regards,
Eyal Shenitzky

On Mon, Apr 15, 2019 at 8:35 PM Wesley Stewart <[email protected]> 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?
> _______________________________________________
> Users mailing list -- [email protected]
> To unsubscribe send an email to [email protected]
> Privacy Statement: https://www.ovirt.org/site/privacy-policy/
> oVirt Code of Conduct:
> https://www.ovirt.org/community/about/community-guidelines/
> List Archives:
> https://lists.ovirt.org/archives/list/[email protected]/message/SZDBAGS6Y66SJATBCVDNSLWYTOYIXHJR/
>


-- 
Regards,
Eyal Shenitzky
_______________________________________________
Users mailing list -- [email protected]
To unsubscribe send an email to [email protected]
Privacy Statement: https://www.ovirt.org/site/privacy-policy/
oVirt Code of Conduct: 
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