[ovirt-users] iSCSI Multipathing

[Devin A. Bougie]

Thanks for following up, Gianluca.  At this point, my main question is why should I configure iSCSI Bonds within the oVirt engine instead of or in addition to configuring iSCSI initiators and multipathd directly in the host's OS.

The multipath.conf created by VDSM works fine with our devices, as do the stock EL6/7 kernels and drivers.  We've had great success using these devices for over a decade in various EL6/7 High-Availability server clusters, and when we configure everything manually they seem to work great with oVirt.  We're just wondering exactly what the advantage is to taking the next step of configuring iSCSI Bonds within the oVirt engine.

For what it's worth, these are Infortrend ESDS devices with redundant controllers and two 10GbE ports per controller.  We connect each host and each controller to two separate switches, so we can simultaneously lose both a controller and a switch without impacting availability.

Thanks again!
Devin

> On Apr 2, 2017, at 7:47 AM, Gianluca Cecchi <gianluca.cecchi at gmail.com> wrote:
> 
> 
> 
> Il 02 Apr 2017 05:20, "Devin A. Bougie" <devin.bougie at cornell.edu> ha scritto:
> We have a new 4.1.1 cluster up and running with OVS switches and an iSCSI hosted_storage and VM data domain (same target, different LUN's).  Everything works fine, and I can configure iscsid and multipathd outside of the oVirt engine to ensure redundancy with our iSCSI device.  However, if I try to configure iSCSI Multipathing within the engine, all of the hosts get stuck in the "Connecting" status and the Data Center and Storage Domains go down.  The hosted engine, however, continues to work just fine.
> 
> Before I provide excerpts from our logs and more details on what we're seeing, it would be helpful to understand better what the advantages are of configuring iSCSI Bonds within the oVirt engine.  Is this mainly a feature for oVirt users that don't have experience configuring and managing iscsid and multipathd directly?  Or, is it important to actually setup iSCSI Bonds within the engine instead of directly in the underlying OS?
> 
> Any advice or links to documentation I've overlooked would be greatly appreciated.
> 
> Many thanks,
> Devin
> 
> What kind of iscsi storage stay are you using?