[ovirt-users] oVIRT 4.1 / iSCSI Multipathing

[Yaniv Kaul]

On Wed, Jul 19, 2017 at 9:13 PM, Vinícius Ferrão <ferrao at if.ufrj.br> wrote:

> Hello,
>
> I’ve skipped this message entirely yesterday. So this is per design?
> Because the best practices of iSCSI MPIO, as far as I know, recommends two
> completely separate paths. If this can’t be achieved with oVirt what’s the
> point of running MPIO?
>

With regular storage it is quite easy to achieve using 'iSCSI bonding'.
I think the Dell storage is a bit different and requires some more
investigation - or experience with it.
 Y.


> May we ask for a bug fix or a feature redesign on this?
>
> MPIO is part of my datacenter, and it was originally build for running
> XenServer, but I’m considering the move to oVirt. MPIO isn’t working right
> and this can be a great no-go for me...
>
> I’m willing to wait and hold my DC project if this can be fixed.
>
> Any answer from the redhat folks?
>
> Thanks,
> V.
>
> > On 18 Jul 2017, at 11:09, Uwe Laverenz <uwe at laverenz.de> wrote:
> >
> > Hi,
> >
> >
> > Am 17.07.2017 um 14:11 schrieb Devin Acosta:
> >
> >> I am still troubleshooting the issue, I haven’t found any resolution to
> my issue at this point yet. I need to figure out by this Friday otherwise I
> need to look at Xen or another solution. iSCSI and oVIRT seems problematic.
> >
> > The configuration of iSCSI-Multipathing via OVirt didn't work for me
> either. IIRC the underlying problem in my case was that I use totally
> isolated networks for each path.
> >
> > Workaround: to make round robin work you have to enable it by editing
> "/etc/multipath.conf". Just add the 3 lines for the round robin setting
> (see comment in the file) and additionally add the "# VDSM PRIVATE" comment
> to keep vdsmd from overwriting your settings.
> >
> > My multipath.conf:
> >
> >
> >> # VDSM REVISION 1.3
> >> # VDSM PRIVATE
> >> defaults {
> >>    polling_interval            5
> >>    no_path_retry               fail
> >>    user_friendly_names         no
> >>    flush_on_last_del           yes
> >>    fast_io_fail_tmo            5
> >>    dev_loss_tmo                30
> >>    max_fds                     4096
> >>    # 3 lines added manually for multipathing:
> >>    path_selector               "round-robin 0"
> >>    path_grouping_policy        multibus
> >>    failback                    immediate
> >> }
> >> # Remove devices entries when overrides section is available.
> >> devices {
> >>    device {
> >>        # These settings overrides built-in devices settings. It does
> not apply
> >>        # to devices without built-in settings (these use the settings
> in the
> >>        # "defaults" section), or to devices defined in the "devices"
> section.
> >>        # Note: This is not available yet on Fedora 21. For more info see
> >>        # https://bugzilla.redhat.com/1253799
> >>        all_devs                yes
> >>        no_path_retry           fail
> >>    }
> >> }
> >
> >
> >
> > To enable the settings:
> >
> >  systemctl restart multipathd
> >
> > See if it works:
> >
> >  multipath -ll
> >
> >
> > HTH,
> > Uwe
> > _______________________________________________
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> > Users at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/users
>
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