[Gluster-users] Fwd: disperse heal speed up

Pranith Kumar Karampuri pkarampu at redhat.com
Thu Aug 11 06:52:38 UTC 2016


On Fri, Aug 5, 2016 at 8:37 PM, Serkan Çoban <cobanserkan at gmail.com> wrote:

> Hi again,
>
> I am seeing the above situation in production environment now.
> One disk on one of my servers broken. I killed the brick process,
> replace the disk, mount it and then I do a gluster v start force.
>
> For a 24 hours period  after replacing disks I see below gluster v
> heal info count increased until 200.000
>
> gluster v heal v0 info | grep "Number of entries" | grep -v "Number of
> entries: 0"
> Number of entries: 205117
> Number of entries: 205231
> ...
> ...
> ...
>
> For about 72 hours It decreased to 40K, and it is going very slowly right
> now.
> What I am observing is very very slow heal speed. There is no errors
> in brick logs.
> There was 900GB data in broken disk and now I see 200GB healed after
> 96 hours after replacing disk.
> There are below warnings in glustershd.log but I think they are harmless.
>
> W [ec_combine.c:866:ec_combine_check] 0-v0-disperse-56: Mismatching
> xdata in answers of LOOKUP
> W [ec_common.c:116:ec_check_status] 0-v0-disperse-56: Operation failed
> on some subvolumes (up=FFFFF, mask=FFFFF, remaining=0, good=FFFF7,
> bad=8)
> W [ec_common.c:71:ec_heal_report] 0-v0-disperse-56: Heal failed
> [invalid argument]
>
> I tried turning on performance.client-io-threads but it did not
> changed anything.
> For 900GB data It will take nearly 8 days to heal. What can I do?
>

Sorry for the delay in response, do you still have this problem?
You can trigger heals using the following command:

find <dir-you-are-interested> -d -exec getfattr -h -n trusted.ec.heal {} \;

If you have 10 top level directories may be you can spawn 10 such processes.



>
> Serkan
>
>
>
> On Fri, Apr 15, 2016 at 1:28 PM, Serkan Çoban <cobanserkan at gmail.com>
> wrote:
> > 100TB is newly created files when brick is down.I rethink the
> > situation and realized that I reformatted all the bricks in case 1 so
> > write speed limit is 26*100MB/disk
> > In case 2 I just reformatted one brick so write speed limited to
> > 100MB/disk...I will repeat the tests using one brick in both cases
> > once with reformat, and once with just killing brick process...
> > Thanks for reply..
> >
> > On Fri, Apr 15, 2016 at 9:27 AM, Xavier Hernandez <xhernandez at datalab.es>
> wrote:
> >> Hi Serkan,
> >>
> >> sorry for the delay, I'm a bit busy lately.
> >>
> >> On 13/04/16 13:59, Serkan Çoban wrote:
> >>>
> >>> Hi Xavier,
> >>>
> >>> Can you help me about the below issue? How can I increase the disperse
> >>> heal speed?
> >>
> >>
> >> It seems weird. Is there any related message in the logs ?
> >>
> >> In this particular test, are the 100TB modified files or newly created
> files
> >> while the brick was down ?
> >>
> >> How many files have been modified ?
> >>
> >>> Also I would be grateful if you have detailed documentation about
> disperse
> >>> heal,
> >>> why heal happens on disperse volume, how it is triggered? Which nodes
> >>> participate in heal process? Any client interaction?
> >>
> >>
> >> Heal process is basically the same used for replicate. There are two
> ways to
> >> trigger a self-heal:
> >>
> >> * when an inconsistency is detected, the client initiates a background
> >> self-heal of the inode
> >>
> >> * the self-heal daemon scans the lists of modified files created by the
> >> index xlator when a modification is made while some node is down. All
> these
> >> files are self-healed.
> >>
> >> Xavi
> >>
> >>
> >>>
> >>> Serkan
> >>>
> >>>
> >>> ---------- Forwarded message ----------
> >>> From: Serkan Çoban <cobanserkan at gmail.com>
> >>> Date: Fri, Apr 8, 2016 at 5:46 PM
> >>> Subject: disperse heal speed up
> >>> To: Gluster Users <gluster-users at gluster.org>
> >>>
> >>>
> >>> Hi,
> >>>
> >>> I am testing heal speed of disperse volume and what I see is 5-10MB/s
> per
> >>> node.
> >>> I increased disperse.background-heals to 32 and
> >>> disperse.heal-wait-qlength to 256, but still no difference.
> >>> One thing I noticed is that, when I kill a brick process, reformat it
> >>> and restart it heal speed is nearly 20x (200MB/s/node)
> >>>
> >>> But when I kill the brick, then write 100TB data, and start brick
> >>> afterwords heal is slow (5-10MB/s/node)
> >>>
> >>> What is the difference between two scenarios? Why one heal is slow and
> >>> other is fast? How can I increase disperse heal speed? Should I
> >>> increase thread count to 128 or 256? I am on 78x(16+4) disperse volume
> >>> and my servers are pretty strong (2x14 cores with 512GB ram, each node
> >>> has 26x8TB disks)
> >>>
> >>> Gluster version is 3.7.10.
> >>>
> >>> Thanks,
> >>> Serkan
> >>>
> >>
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>



-- 
Pranith
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