Hello Gionatan,
Using Gluster brick in a RAID configuration might be safer and require less work from Gluster admins but, it is a waste of disk space.
Gluster bricks are replicated "assuming you're creating a distributed-replica volume" so when brick went down, it should be easy to recover it and should not affect the client's IO.
We are using JBOD in all of our Gluster setups, overall, performance is good, and replacing a brick would work "most" of the time without issues.
On Sun, Jun 21, 2020 at 8:43 PM Gionatan Danti <g.danti@xxxxxxxxxx> wrote:
Il 2020-06-21 14:20 Strahil Nikolov ha scritto:
> With every community project , you are in the position of a Betta
> Tester - no matter Fedora, Gluster or CEPH. So far , I had
> issues with upstream projects only diring and immediately after
> patching - but this is properly mitigated with a reasonable
> patching strategy (patch test environment and several months later
> patch prod with the same repos).
> Enterprise Linux breaks (and alot) having 10-times more users and
> use cases, so you cannot expect to start to use Gluster and assume
> that a free peoject won't break at all.
> Our part in this project is to help the devs to create a test case for
> our workload , so regressions will be reduced to minimum.
Well, this is true, and both devs & community deserve a big thanks for
all the work done.
> In the past 2 years, we got 2 major issues with VMware VSAN and 1
> major issue with a Enterprise Storage cluster (both solutions are
> quite expensive) - so I always recommend proper testing of your
> software .
Interesting, I am almost tempted to ask you what issue you had with
vSAN, but this is not the right mailing list ;)
> From my observations, almost nobody is complaining about Ganesha in
> the mailing list -> 50% are having issues with geo replication,20%
> are having issues with small file performance and the rest have
> issues with very old version of gluster -> v5 or older.
Mmm, I would swear to have read quite a few posts where the problem was
solved by migrating away from NFS Ganesha. Still, for hyperconverged
setup a problem remains: NFS on loopback/localhost is not 100% supported
(or, at least, RH is not willing to declare it supportable/production
ready [1]). A fuse mount would be the more natural way to access the
underlying data.
> I can't say that a replace-brick on a 'replica 3' volume is more
> riskier than a rebuild of a raid, but I have noticed that nobody is
> following Red Hat's guide to use either:
> - a Raid6 of 12 Disks (2-3 TB big)
> - a Raid10 of 12 Disks (2-3 TB big)
> - JBOD disks in 'replica 3' mode (i'm not sure about the size RH
> recommends, most probably 2-3 TB)
> So far, I didn' have the opportunity to run on JBODs.
For the RAID6/10 setup, I found no issues: simply replace the broken
disk without involing Gluster at all. However, this also means facing
the "iops wall" I described earlier for single-brick node. Going
full-Guster with JBODs would be interesting from a performance
standpoint, but this complicate eventual recovery from bad disks.
Does someone use Gluster in JBOD mode? If so, can you share your
experience?
Thanks.
[1] https://access.redhat.com/solutions/22231 (accound required)
[2] https://bugzilla.redhat.com/show_bug.cgi?id=489889 (old, but I can
not find anything newer)
--
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it [1]
email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx
GPG public key ID: FF5F32A8
Respectfully
Mahdi
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