[Users] Experience with low cost NFS-Storage as VM-Storage?

[squadra]

another point is, that a correct configured multipathing is way more solid
when it comes to a single path outage. at the software side, i have seen
countless nfs servers which where unresponsive because of lockd issues for
example, and only a reboot fixed this since its kernel based.

another contra for me is, that its rather complicated and a 50/50 chance
that a nfs failover in a nfs ha setup works without any clients dying.

dont get me wrong, nfs is great for small setups. its easy to setup, easy
to scale, i use it very widespread for content sharing and homedirs. but i
am healed regarding vm images on nfs.


On Thu, Jan 9, 2014 at 8:48 AM, Karli Sjöberg <Karli.Sjoberg at slu.se> wrote:

> On Thu, 2014-01-09 at 08:35 +0100, squadra wrote:
> > Right, try multipathing with nfs :)
>
> Yes, that´s what I meant, maybe could have been more clear about that,
> sorry. Multipathing (and the load-balancing it brings) is what really
> separates iSCSI from NFS.
>
> What I´d be interested in knowing is at what breaking-point, not having
> multipathing becomes an issue. I mean, we might not have such a big
> VM-park, about 300-400 VMs. But so far running without multipathing
> using good ole' NFS and no performance issues this far. Would be good to
> know beforehand if we´re headed for a wall of some sorts, and about
> "when" we´ll hit it...
>
> /K
>
> >
> > On Jan 9, 2014 8:30 AM, "Karli Sjöberg" <Karli.Sjoberg at slu.se> wrote:
> >         On Thu, 2014-01-09 at 07:10 +0000, Markus Stockhausen wrote:
> >         > > Von: users-bounces at ovirt.org [users-bounces at ovirt.org]" im
> >         Auftrag von "squadra [squadra at gmail.com]
> >         > > Gesendet: Mittwoch, 8. Januar 2014 17:15
> >         > > An: users at ovirt.org
> >         > > Betreff: Re: [Users] Experience with low cost NFS-Storage
> >         as VM-Storage?
> >         > >
> >         > > better go for iscsi or something else... i whould avoid
> >         nfs for vm hosting
> >         > > Freebsd10 delivers kernel iscsitarget now, which works
> >         great so far. or go with omnios to get comstar iscsi, which is
> >         a rocksolid solution
> >         > >
> >         > > Cheers,
> >         > >
> >         > > Juergen
> >         >
> >         > That is usually a matter of taste and the available
> >         environment.
> >         > The minimal differences in performance usually only show up
> >         > if you drive the storage to its limits. I guess you could
> >         help Sven
> >         > better if you had some hard facts why to favour ISCSI.
> >         >
> >         > Best regards.
> >         >
> >         > Markus
> >
> >         Only technical difference I can think of is the iSCSI-level
> >         load-balancing. With NFS you set up the network with LACP and
> >         let that
> >         load-balance for you (and you should probably do that with
> >         iSCSI as well
> >         but you don´t strictly have to). I think it has to do with a
> >         chance of
> >         trying to go beyond the capacity of 1 network interface at the
> >         same
> >         time, from one Host (higher bandwidth) that makes people try
> >         iSCSI
> >         instead of plain NFS. I have tried that but was never able to
> >         achieve
> >         that effect, so in our situation, there´s no difference. In
> >         comparing
> >         them both in benchmarks, there was no performance difference
> >         at all, at
> >         least for our storage systems that are based on FreeBSD.
> >
> >         /K
>
>


-- 

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