[Users] iSCSI Storage mirror

[Tal Nisan]

As for the oVirt point of view, oVirt does not support storage mirroring 
out of the box unless it used with Gluster FS
As for the iSCSI mirroring, what exactly do you mean by mirroring? If 
you refer to replication then you should probably use Gluster for that 
matter, if not, can you please send me the actions you are to do 
manually to try and achieve this mirroring so I can understand better

On 03/09/2013 11:40 PM, Jaco wrote:
> Hi guys,
>
> Got my system (3.2 on CentOS 6.3 - PoC lab v.0.99999) working fairly 
> OK, with a few issues that's of concern to me.
>
> I've now started using iSCSI storage, but kept running into an issue 
> where the VM's would go into a paused state.
>
> A bit of digging in the logs show that it's because of a timeout issue 
> talking to the iSCSI server/target, which for me raises the spectre of 
> potential corruption, especially under load.
> Couldn't understand how this was possible, as I went out & bought some 
> dedicated hardware to set up a totally separate & isolated "storage" 
> network, but ended up simply running a cross-over UTP between the 
> machines (process-of-elimination & all that), but the issue persisted.
> This morning I found that one of the mirrored drives started failing, 
> so (until I've replaced the drive & discovered otherwise) I suspect 
> that may be the possible cause of the issue.
>
> What occurred to me last night, as this thing was keeping me awake, is 
> that this might not be the *best* course of action, and started 
> thinking that maybe another way of doing it, especially since oVirt 
> does some fairly low-level LVM stuff, is to rather store the VM's on a 
> local drive, get far better IOPS than I could hope for with iSCSI over 
> GBE, and rather set up the iSCSI to mirror the local device.
> That way the data is still available on the target in the event a 
> fail-over/migration needs to take place, but that I'm reducing the 
> risks a bit while improving overall performance.
>
> Is there a way to do this via oVirt, or would I have to do it manually 
> by setting up storage locally & set up the mirroring via iSCSI 
> manually as an OS-level?
> And if so, what would I be looking for & what sort of caveats would I 
> have to keep in mind in order to make this setup suitable for use by 
> multiple hosts in the event a (live-)migration needs to take place? 
> (I'm pretty new at the iSCSI-thing & LVM knowledge is just passable)
>
> I'd appreciate anyone's insights into this subject
>
> Kind regards
>
> - Jaco
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