[ovirt-users] iSCSI Multipathing -> host inactive

[Nicolas Ecarnot]

Le 26/08/2016 à 12:33, InterNetX - Juergen Gotteswinter a écrit :
>
>
> Am 25.08.2016 um 15:53 schrieb Yaniv Kaul:
>>
>>
>> On Wed, Aug 24, 2016 at 6:15 PM, InterNetX - Juergen Gotteswinter
>> <juergen.gotteswinter at internetx.com
>> <mailto:juergen.gotteswinter at internetx.com>> wrote:
>>
>>     iSCSI & Ovirt is an awful combination, no matter if multipathed or
>>     bonded. its always gambling how long it will work, and when it fails why
>>     did it fail.
>>
>>
>> I disagree. In most cases, it's actually a lower layer issues. In most
>> cases, btw, it's because multipathing was not configured (or not
>> configured correctly).
>>
>
> experience tells me it is like is said, this was something i have seen
> from 3.0 up to 3.6. Ovirt, and - suprprise - RHEV. Both act the same
> way. I am absolutly aware of Multpath Configurations, iSCSI Multipathing
> is very widespread in use in our DC. But such problems are an excluse
> Ovirt/RHEV Feature.
>
>>
>>
>>     its supersensitive to latency, and superfast with setting an host to
>>     inactive because the engine thinks something is wrong with it. in most
>>     cases there was no real reason for.
>>
>>
>> Did you open bugs for those issues? I'm not aware of 'no real reason'
>> issues.
>>
>
> Support Tickets for Rhev Installation, after Support (even after massive
> escalation requests) kept telling me the same again and again i gave up
> and we dropped the RHEV Subscriptions to Migrate the VMS to a different
> Plattform Solution (still iSCSI Backend). Problems gone.
>
>
>>
>>
>>     we had this in several different hardware combinations, self built
>>     filers up on FreeBSD/Illumos & ZFS, Equallogic SAN, Nexenta Filer
>>
>>     Been there, done that, wont do again.
>>
>>
>> We've had good success and reliability with most enterprise level
>> storage, such as EMC, NetApp, Dell filers.
>> When properly configured, of course.
>> Y.
>>
>
> Dell Equallogic? Cant really believe since Ovirt / Rhev and the
> Equallogic Network Configuration wont play nice together (EQL wants all
> Interfaces in the same Subnet). And they only work like expected when
> there Hit Kit Driverpackage is installed. Without Path Failover is like
> russian Roulette. But Ovirt hates the Hit Kit, so this Combo ends up in
> a huge mess, because Ovirt does changes to iSCSI, as well as the Hit Kit
> -> Kaboom. Host not available.
>
> There are several KB Articles in the RHN, without real Solution.

I'm working with Dell, EMC and EQL for 7 years, and with oVirt for 4 
years, and I must recognize that what Juergen said is true : HIT is not 
compatible with the way oVirt is using iSCSI (or the other way round).
What he says about LVM is also true.
I still love oVirt, and won't quit. I'm just very patient and hoping my 
BZ and RFE get fixed.


-- 
Nicolas ECARNOT