[Gluster-users] Gluter 3.12.12: performance during heal and in general

[Hu Bert]

Hi Pranith,

thanks a lot for your efforts and for tracking "my" problem with an issue. :-)

I've set this params on the gluster volume and will start the
'find...' command within a short time. I'll probably add another
answer to the list to document the progress.

btw. - you had some typos:
gluster volume set <volname> cluster.cluster.heal-wait-queue-length
10000 => cluster is doubled
gluster volume set <volname> cluster.data-self-heal-window-size 16 =>
it's actually cluster.self-heal-window-size

but actually no problem :-)

Just curious: would gluster 4.1 improve the performance for healing
and in general for "my" scenario?

2018-07-26 8:56 GMT+02:00 Pranith Kumar Karampuri <pkarampu at redhat.com>:
> Thanks a lot for detailed write-up, this helps find the bottlenecks easily.
> On a high level, to handle this directory hierarchy i.e. lots of directories
> with files, we need to improve healing
> algorithms. Based on the data you provided, we need to make the following
> enhancements:
>
> 1) At the moment directories are healed one at a time, but files can be
> healed upto 64 in parallel per replica subvolume.
> So if you have nX2 or nX3 distributed subvolumes, it can heal 64n number of
> files in parallel.
>
> I raised https://github.com/gluster/glusterfs/issues/477 to track this. In
> the mean-while you can use the following work-around:
> a) Increase background heals on the mount:
> gluster volume set <volname> cluster.background-self-heal-count 256
> gluster volume set <volname> cluster.cluster.heal-wait-queue-length 10000
> find <mnt> -type d | xargs stat
>
> one 'find' will trigger 10256 directories. So you may have to do this
> periodically until all directories are healed.
>
> 2) Self-heal heals a file 128KB at a time(data-self-heal-window-size). I
> think for your environment bumping upto MBs is better. Say 2MB i.e.
> 16*128KB?
>
> Command to do that is:
> gluster volume set <volname> cluster.data-self-heal-window-size 16
>
>
> On Thu, Jul 26, 2018 at 10:40 AM, Hu Bert <revirii at googlemail.com> wrote:
>>
>> Hi Pranith,
>>
>> Sry, it took a while to count the directories. I'll try to answer your
>> questions as good as possible.
>>
>> > What kind of data do you have?
>> > How many directories in the filesystem?
>> > On average how many files per directory?
>> > What is the depth of your directory hierarchy on average?
>> > What is average filesize?
>>
>> We have mostly images (more than 95% of disk usage, 90% of file
>> count), some text files (like css, jsp, gpx etc.) and some binaries.
>>
>> There are about 190.000 directories in the file system; maybe there
>> are some more because we're hit by bug 1512371 (parallel-readdir =
>> TRUE prevents directories listing). But the number of directories
>> could/will rise in the future (maybe millions).
>>
>> files per directory: ranges from 0 to 100, on average it should be 20
>> files per directory (well, at least in the deepest dirs, see
>> explanation below).
>>
>> Average filesize: ranges from a few hundred bytes up to 30 MB, on
>> average it should be 2-3 MB.
>>
>> Directory hierarchy: maximum depth as seen from within the volume is
>> 6, the average should be 3.
>>
>> volume name: shared
>> mount point on clients: /data/repository/shared/
>> below /shared/ there are 2 directories:
>> - public/: mainly calculated images (file sizes from a few KB up to
>> max 1 MB) and some resouces (small PNGs with a size of a few hundred
>> bytes).
>> - private/: mainly source images; file sizes from 50 KB up to 30MB
>>
>> We migrated from a NFS server (SPOF) to glusterfs and simply copied
>> our files. The images (which have an ID) are stored in the deepest
>> directories of the dir tree. I'll better explain it :-)
>>
>> directory structure for the images (i'll omit some other miscellaneous
>> stuff, but it looks quite similar):
>> - ID of an image has 7 or 8 digits
>> - /shared/private/: /(first 3 digits of ID)/(next 3 digits of ID)/$ID.jpg
>> - /shared/public/: /(first 3 digits of ID)/(next 3 digits of
>> ID)/$ID/$misc_formats.jpg
>>
>> That's why we have that many (sub-)directories. Files are only stored
>> in the lowest directory hierarchy. I hope i could make our structure
>> at least a bit more transparent.
>>
>> i hope there's something we can do to raise performance a bit. thx in
>> advance :-)
>>
>>
>> 2018-07-24 10:40 GMT+02:00 Pranith Kumar Karampuri <pkarampu at redhat.com>:
>> >
>> >
>> > On Mon, Jul 23, 2018 at 4:16 PM, Hu Bert <revirii at googlemail.com> wrote:
>> >>
>> >> Well, over the weekend about 200GB were copied, so now there are
>> >> ~400GB copied to the brick. That's far beyond a speed of 10GB per
>> >> hour. If I copied the 1.6 TB directly, that would be done within max 2
>> >> days. But with the self heal this will take at least 20 days minimum.
>> >>
>> >> Why is the performance that bad? No chance of speeding this up?
>> >
>> >
>> > What kind of data do you have?
>> > How many directories in the filesystem?
>> > On average how many files per directory?
>> > What is the depth of your directory hierarchy on average?
>> > What is average filesize?
>> >
>> > Based on this data we can see if anything can be improved. Or if there
>> > are
>> > some
>> > enhancements that need to be implemented in gluster to address this kind
>> > of
>> > data layout
>> >>
>> >>
>> >> 2018-07-20 9:41 GMT+02:00 Hu Bert <revirii at googlemail.com>:
>> >> > hmm... no one any idea?
>> >> >
>> >> > Additional question: the hdd on server gluster12 was changed, so far
>> >> > ~220 GB were copied. On the other 2 servers i see a lot of entries in
>> >> > glustershd.log, about 312.000 respectively 336.000 entries there
>> >> > yesterday, most of them (current log output) looking like this:
>> >> >
>> >> > [2018-07-20 07:30:49.757595] I [MSGID: 108026]
>> >> > [afr-self-heal-common.c:1724:afr_log_selfheal] 0-shared-replicate-3:
>> >> > Completed data selfheal on 0d863a62-0dd8-401c-b699-2b642d9fd2b6.
>> >> > sources=0 [2]  sinks=1
>> >> > [2018-07-20 07:30:49.992398] I [MSGID: 108026]
>> >> > [afr-self-heal-metadata.c:52:__afr_selfheal_metadata_do]
>> >> > 0-shared-replicate-3: performing metadata selfheal on
>> >> > 0d863a62-0dd8-401c-b699-2b642d9fd2b6
>> >> > [2018-07-20 07:30:50.243551] I [MSGID: 108026]
>> >> > [afr-self-heal-common.c:1724:afr_log_selfheal] 0-shared-replicate-3:
>> >> > Completed metadata selfheal on 0d863a62-0dd8-401c-b699-2b642d9fd2b6.
>> >> > sources=0 [2]  sinks=1
>> >> >
>> >> > or like this:
>> >> >
>> >> > [2018-07-20 07:38:41.726943] I [MSGID: 108026]
>> >> > [afr-self-heal-metadata.c:52:__afr_selfheal_metadata_do]
>> >> > 0-shared-replicate-3: performing metadata selfheal on
>> >> > 9276097a-cdac-4d12-9dc6-04b1ea4458ba
>> >> > [2018-07-20 07:38:41.855737] I [MSGID: 108026]
>> >> > [afr-self-heal-common.c:1724:afr_log_selfheal] 0-shared-replicate-3:
>> >> > Completed metadata selfheal on 9276097a-cdac-4d12-9dc6-04b1ea4458ba.
>> >> > sources=[0] 2  sinks=1
>> >> > [2018-07-20 07:38:44.755800] I [MSGID: 108026]
>> >> > [afr-self-heal-entry.c:887:afr_selfheal_entry_do]
>> >> > 0-shared-replicate-3: performing entry selfheal on
>> >> > 9276097a-cdac-4d12-9dc6-04b1ea4458ba
>> >> >
>> >> > is this behaviour normal? I'd expect these messages on the server
>> >> > with
>> >> > the failed brick, not on the other ones.
>> >> >
>> >> > 2018-07-19 8:31 GMT+02:00 Hu Bert <revirii at googlemail.com>:
>> >> >> Hi there,
>> >> >>
>> >> >> sent this mail yesterday, but somehow it didn't work? Wasn't
>> >> >> archived,
>> >> >> so please be indulgent it you receive this mail again :-)
>> >> >>
>> >> >> We are currently running a replicate setup and are experiencing a
>> >> >> quite poor performance. It got even worse when within a couple of
>> >> >> weeks 2 bricks (disks) crashed. Maybe some general information of
>> >> >> our
>> >> >> setup:
>> >> >>
>> >> >> 3 Dell PowerEdge R530 (Xeon E5-1650 v3 Hexa-Core, 64 GB DDR4, OS on
>> >> >> separate disks); each server has 4 10TB disks -> each is a brick;
>> >> >> replica 3 setup (see gluster volume status below). Debian stretch,
>> >> >> kernel 4.9.0, gluster version 3.12.12. Servers and clients are
>> >> >> connected via 10 GBit ethernet.
>> >> >>
>> >> >> About a month ago and 2 days ago a disk died (on different servers);
>> >> >> disk were replaced, were brought back into the volume and full self
>> >> >> heal started. But the speed for this is quite... disappointing. Each
>> >> >> brick has ~1.6TB of data on it (mostly the infamous small files).
>> >> >> The
>> >> >> full heal i started yesterday copied only ~50GB within 24 hours (48
>> >> >> hours: about 100GB) - with
>> >> >> this rate it would take weeks until the self heal finishes.
>> >> >>
>> >> >> After the first heal (started on gluster13 about a month ago, took
>> >> >> about 3 weeks) finished we had a terrible performance; CPU on one or
>> >> >> two of the nodes (gluster11, gluster12) was up to 1200%, consumed by
>> >> >> the brick process of the former crashed brick (bricksdd1),
>> >> >> interestingly not on the server with the failed this, but on the
>> >> >> other
>> >> >> 2 ones...
>> >> >>
>> >> >> Well... am i doing something wrong? Some options wrongly configured?
>> >> >> Terrible setup? Anyone got an idea? Any additional information
>> >> >> needed?
>> >> >>
>> >> >>
>> >> >> Thx in advance :-)
>> >> >>
>> >> >> gluster volume status
>> >> >>
>> >> >> Volume Name: shared
>> >> >> Type: Distributed-Replicate
>> >> >> Volume ID: e879d208-1d8c-4089-85f3-ef1b3aa45d36
>> >> >> Status: Started
>> >> >> Snapshot Count: 0
>> >> >> Number of Bricks: 4 x 3 = 12
>> >> >> Transport-type: tcp
>> >> >> Bricks:
>> >> >> Brick1: gluster11:/gluster/bricksda1/shared
>> >> >> Brick2: gluster12:/gluster/bricksda1/shared
>> >> >> Brick3: gluster13:/gluster/bricksda1/shared
>> >> >> Brick4: gluster11:/gluster/bricksdb1/shared
>> >> >> Brick5: gluster12:/gluster/bricksdb1/shared
>> >> >> Brick6: gluster13:/gluster/bricksdb1/shared
>> >> >> Brick7: gluster11:/gluster/bricksdc1/shared
>> >> >> Brick8: gluster12:/gluster/bricksdc1/shared
>> >> >> Brick9: gluster13:/gluster/bricksdc1/shared
>> >> >> Brick10: gluster11:/gluster/bricksdd1/shared
>> >> >> Brick11: gluster12:/gluster/bricksdd1_new/shared
>> >> >> Brick12: gluster13:/gluster/bricksdd1_new/shared
>> >> >> Options Reconfigured:
>> >> >> cluster.shd-max-threads: 4
>> >> >> performance.md-cache-timeout: 60
>> >> >> cluster.lookup-optimize: on
>> >> >> cluster.readdir-optimize: on
>> >> >> performance.cache-refresh-timeout: 4
>> >> >> performance.parallel-readdir: on
>> >> >> server.event-threads: 8
>> >> >> client.event-threads: 8
>> >> >> performance.cache-max-file-size: 128MB
>> >> >> performance.write-behind-window-size: 16MB
>> >> >> performance.io-thread-count: 64
>> >> >> cluster.min-free-disk: 1%
>> >> >> performance.cache-size: 24GB
>> >> >> nfs.disable: on
>> >> >> transport.address-family: inet
>> >> >> performance.high-prio-threads: 32
>> >> >> performance.normal-prio-threads: 32
>> >> >> performance.low-prio-threads: 32
>> >> >> performance.least-prio-threads: 8
>> >> >> performance.io-cache: on
>> >> >> server.allow-insecure: on
>> >> >> performance.strict-o-direct: off
>> >> >> transport.listen-backlog: 100
>> >> >> server.outstanding-rpc-limit: 128
>> >> _______________________________________________
>> >> Gluster-users mailing list
>> >> Gluster-users at gluster.org
>> >> https://lists.gluster.org/mailman/listinfo/gluster-users
>> >
>> >
>> >
>> >
>> > --
>> > Pranith
>
>
>
>
> --
> Pranith