On Tue, Oct 4, 2016 at 7:03 PM, Michal Skrivanek <
michal.skrivanek(a)redhat.com> wrote:
> On 4 Oct 2016, at 09:51, Gary Lloyd <g.lloyd(a)keele.ac.uk> wrote:
>
> Hi
>
> We have Ovirt 3.65 with a Dell Equallogic SAN and we use Direct Luns for
all our VMs.
> At the weekend during early hours an Equallogic controller failed over
to its standby on one of our arrays and this caused about 20 of our VMs to
be paused due to IO problems.
>
> I have also noticed that this happens during Equallogic firmware
upgrades since we moved onto Ovirt 3.65.
>
> As recommended by Dell disk timeouts within the VMs are set to 60
seconds when they are hosted on an EqualLogic SAN.
>
> Is there any other timeout value that we can configure in vdsm.conf to
stop VMs from getting paused when a controller fails over ?
not really. but things are not so different when you look at it from the
guest perspective. If the intention is to hide the fact that there is a
problem and the guest should just see a delay (instead of dealing with
error) then pausing and unpausing is the right behavior. From guest point
of view this is just a delay it sees.
>
> Also is there anything that we can tweak to automatically unpause the
VMs once connectivity with the arrays is re-established ?
that should happen when the storage domain monitoring detects error and
then
reactivate(http://gerrit.ovirt.org/16244). It may be that since you
have direct luns it’s not working with those….dunno, storage people should
chime in I guess...
We don't monitor direct luns, only storage domains, so we do not support
resuming vms using direct luns.
multipath does monitor all devices, so we could monitor the devices status
via multipath, and resume paused vms when a device move from faulty
state to active state.
Maybe open an RFE for this?
Nir