[Gluster-users] Failed rebalance resulting in major problems

Lukáš Bezdička lukas.bezdicka at gooddata.com
Thu Nov 7 10:20:39 UTC 2013

I strongly suggest not using 3.3.1 or whole 3.3 branch. I would only go for
3.4.1 on something close to production and even there I wouldn't yet use
rebalance/shrinking. We give gluster heavy testing before it goes to
production and about updating, why don't you build your own packages? We
are maintaining our builds for several years now with our patches which
gladly end up in gluster upstream sooner or later.

On Wed, Nov 6, 2013 at 9:57 PM, Justin Dossey <jbd at podomatic.com> wrote:

> Joe,
> You're right-- I probably should have dialed it back a bit! It's
> frustrating sometimes when I post about such a major issue and never see
> any reply.
> In my case, I run into gfid bugs regularly, almost always in situations
> where I have copied an entire directory tree into a GlusterFS mount.  There
> have been no connectivity issues between nodes, no node restarts, etc, for
> months, but once in a while, I get a gfid mismatch and must manually
> correct the situation.
> I would certainly purchase GlusterFS support if I had any option other
> than Red Hat-- they only support Red Hat Storage and that isn't a good fit
> for my environment at this time.  If GlusterFS is successful the way it
> could be, there will definitely be an opportunity for a firm to support it
> on non-RedHat platforms.
> FWIW, I've created a Github repo to store my scripts for navigating
> GlusterFS issues.  If they remain relevant and the repo gets activity, I'll
> go to Gluster Forge.  https://github.com/justindossey/gluster-scripts
> On Wed, Nov 6, 2013 at 12:15 PM, Joe Julian <joe at julianfamily.org> wrote:
>>  On 11/06/2013 11:52 AM, Justin Dossey wrote:
>> Shawn,
>>  I had a very similar experience with a rebalance on 3.3.1, and it took
>> weeks to get everything straightened out.  I would be happy to share the
>> scripts I wrote to correct the permissions issues if you wish, though I'm
>> not sure it would be appropriate to share them directly on this list.
>>  Perhaps I should just create a project on Github that is devoted to
>> collecting scripts people use to fix their GlusterFS environments!
>>  After that (awful) experience, I am loath to run further rebalances.
>>  I've even spent days evaluating alternatives to GlusterFS, as my
>> experience with this list over the last six months indicates that support
>> for community users is minimal, even in the face of major bugs such as the
>> one with rebalancing and the continuing "gfid different on subvolume" bugs
>> with 3.3.2.
>> I'm one of oldest GlusterFS users around here and one of the biggest
>> proponents and even I have been loath to rebalance until 3.4.1.
>> There are no open bugs for gfid mismatches that I could find. The last
>> time someone mentioned that error in IRC it was 2am, I was at a convention,
>> and I told the user how to solve that problem (
>> http://irclog.perlgeek.de/gluster/2013-06-14#i_7196149 ). It was caused
>> by split-brain. If you have a bug, it would be more productive to file it
>> rather than make negative comments about a community of people that have no
>> requirement to help anybody, but do it anyway just because they're nice
>> people.
>> This is going to sound snarky because it's in text, but I mean this
>> sincerely. If community support is not sufficient, you might consider
>> purchasing support from a company that provides it professionally.
>>  Let me know what you think of the Github thing and I'll proceed
>> appropriately.
>> Even better, put them up on http://forge.gluster.org
>> On Tue, Nov 5, 2013 at 9:05 PM, Shawn Heisey <gluster at elyograg.org>wrote:
>>> We recently added storage servers to our gluster install, running 3.3.1
>>> on CentOS 6.  It went from 40TB usable (8x2 distribute-replicate) to
>>> 80TB usable (16x2).  There was a little bit over 20TB used space on the
>>> volume.
>>> The add-brick went through without incident, but the rebalance failed
>>> after moving 1.5TB of the approximately 10TB that needed to be moved.  A
>>> side issue is that it took four days for that 1.5TB to move.  I'm aware
>>> that gluster has overhead, and that there's only so much speed you can
>>> get out of gigabit, but a 100Mb/s half-duplex link could have copied the
>>> data faster if it had been a straight copy.
>>> After I discovered that the rebalance had failed, I noticed that there
>>> were other problems.  There are a small number of completely lost files
>>> (91 that I know about so far), a huge number of permission issues (over
>>> 800,000 files changed to 000), and about 32000 files that are throwing
>>> read errors via the fuse/nfs mount but seem to be available directly on
>>> bricks.  That last category of problem file has the sticky bit set, with
>>> almost all of them having ---------T permissions.  The good files on
>>> bricks typically have the same permissions, but are readable by root.  I
>>> haven't worked out the scripting necessary to automate all the fixing
>>> that needs to happen yet.
>>> We really need to know what happened.  We do plan to upgrade to 3.4.1,
>>> but there were some reasons that we didn't want to upgrade before adding
>>> storage.
>>> * Upgrading will result in service interruption to our clients, which
>>> mount via NFS.  It would likely be just a hiccup, with quick failover,
>>> but it's still a service interruption.
>>> * We have a pacemaker cluster providing the shared IP address for NFS
>>> mounting.  It's running CentOS 6.3.  A "yum upgrade" to upgrade gluster
>>> will also upgrade to CentOS 6.4.  The pacemaker in 6.4 is incompatible
>>> with the pacemaker in 6.3, which will likely result in
>>> longer-than-expected downtime for the shared IP address.
>>> * We didn't want to risk potential problems with running gluster 3.3.1
>>> on the existing servers and 3.4.1 on the new servers.
>>> * We needed the new storage added right away, before we could schedule
>>> maintenance to deal with the upgrade issues.
>>> Something that would be extremely helpful would be obtaining the
>>> services of an expert-level gluster consultant who can look over
>>> everything we've done to see if there is anything we've done wrong and
>>> how we might avoid problems in the future.  I don't know how much the
>>> company can authorize for this, but we obviously want it to be as cheap
>>> as possible.  We are in Salt Lake City, UT, USA.  It would be preferable
>>> to have the consultant be physically present at our location.
>>> I'm working on redacting one bit of identifying info from our rebalance
>>> log, then I can put it up on dropbox for everyone to examine.
>>> Thanks,
>>> Shawn
>>> _______________________________________________
>>> Gluster-users mailing list
>>> Gluster-users at gluster.org
>>> http://supercolony.gluster.org/mailman/listinfo/gluster-users
>>  --
>> Justin Dossey
>> CTO, PodOmatic
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> --
> Justin Dossey
> CTO, PodOmatic
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://supercolony.gluster.org/mailman/listinfo/gluster-users
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