Re: Extremely slow file listing in folders with many files

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Hi,

Does the gluster team have any feedback about this? Resolving the "Found anomalies" issues may be key to resolving dir list speed issues.

Sincerely,
Artem

--
Founder, Android PoliceAPK Mirror, Illogical Robot LLC


On Thu, Apr 30, 2020 at 10:36 PM Strahil Nikolov <hunter86_bg@xxxxxxxxx> wrote:
On April 30, 2020 9:05:19 PM GMT+03:00, Artem Russakovskii <archon810@xxxxxxxxx> wrote:
>I did this on the same prod instance just now.
>
>'find' on a fuse gluster dir with 40k+ files:
>1st run: 3m56.261s
>2nd run: 0m24.970s
>3rd run: 0m24.099s
>
>At this point, I killed all gluster services on one of the 4 servers
>and
>verified that that brick went offline.
>
>1st run: 0m38.131s
>2nd run: 0m19.369s
>3rd run: 0m23.576s
>
>Nothing conclusive really IMO.
>
>Sincerely,
>Artem
>
>--
>Founder, Android Police <http://www.androidpolice.com>, APK Mirror
><http://www.apkmirror.com/>, Illogical Robot LLC
>beerpla.net | @ArtemR <http://twitter.com/ArtemR>
>
>
>On Thu, Apr 30, 2020 at 9:55 AM Strahil Nikolov <hunter86_bg@xxxxxxxxx>
>wrote:
>
>> On April 30, 2020 6:27:10 PM GMT+03:00, Artem Russakovskii <
>> archon810@xxxxxxxxx> wrote:
>> >Hi Strahil, in the original email I included both the times for the
>> >first
>> >and subsequent reads on the fuse mounted gluster volume as well as
>the
>> >xfs
>> >filesystem the gluster data resides on (this is the brick, right?).
>> >
>> >On Thu, Apr 30, 2020, 7:44 AM Strahil Nikolov
><hunter86_bg@xxxxxxxxx>
>> >wrote:
>> >
>> >> On April 30, 2020 4:24:23 AM GMT+03:00, Artem Russakovskii <
>> >> archon810@xxxxxxxxx> wrote:
>> >> >Hi all,
>> >> >
>> >> >We have 500GB and 10TB 4x1 replicate xfs-based gluster volumes,
>and
>> >the
>> >> >10TB one especially is extremely slow to do certain things with
>(and
>> >> >has
>> >> >been since gluster 3.x when we started). We're currently on 5.13.
>> >> >
>> >> >The number of files isn't even what I'd consider that great -
>under
>> >> >100k
>> >> >per dir.
>> >> >
>> >> >Here are some numbers to look at:
>> >> >
>> >> >On gluster volume in a dir of 45k files:
>> >> >The first time
>> >> >
>> >> >time find | wc -l
>> >> >45423
>> >> >real    8m44.819s
>> >> >user    0m0.459s
>> >> >sys     0m0.998s
>> >> >
>> >> >And again
>> >> >
>> >> >time find | wc -l
>> >> >45423
>> >> >real    0m34.677s
>> >> >user    0m0.291s
>> >> >sys     0m0.754s
>> >> >
>> >> >
>> >> >If I run the same operation on the xfs block device itself:
>> >> >The first time
>> >> >
>> >> >time find | wc -l
>> >> >45423
>> >> >real    0m13.514s
>> >> >user    0m0.144s
>> >> >sys     0m0.501s
>> >> >
>> >> >And again
>> >> >
>> >> >time find | wc -l
>> >> >45423
>> >> >real    0m0.197s
>> >> >user    0m0.088s
>> >> >sys     0m0.106s
>> >> >
>> >> >
>> >> >I'd expect a performance difference here but just as it was
>several
>> >> >years
>> >> >ago when we started with gluster, it's still huge, and simple
>file
>> >> >listings
>> >> >are incredibly slow.
>> >> >
>> >> >At the time, the team was looking to do some optimizations, but
>I'm
>> >not
>> >> >sure this has happened.
>> >> >
>> >> >What can we do to try to improve performance?
>> >> >
>> >> >Thank you.
>> >> >
>> >> >
>> >> >
>> >> >Some setup values follow.
>> >> >
>> >> >xfs_info /mnt/SNIP_block1
>> >> >meta-data=""              isize=512    agcount=103,
>> >> >agsize=26214400
>> >> >blks
>> >> >         =                       sectsz=512   attr=2,
>projid32bit=1
>> >> >      =                       crc=1        finobt=1, sparse=0,
>> >rmapbt=0
>> >> >         =                       reflink=0
>> >> >data     =                       bsize=4096   blocks=2684354560,
>> >> >imaxpct=25
>> >> >         =                       sunit=0      swidth=0 blks
>> >> >naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
>> >> >log      =internal log           bsize=4096   blocks=51200,
>> >version=2
>> >> >        =                       sectsz=512   sunit=0 blks,
>> >lazy-count=1
>> >> >realtime =none                   extsz=4096   blocks=0,
>rtextents=0
>> >> >
>> >> >Volume Name: SNIP_data1
>> >> >Type: Replicate
>> >> >Volume ID: SNIP
>> >> >Status: Started
>> >> >Snapshot Count: 0
>> >> >Number of Bricks: 1 x 4 = 4
>> >> >Transport-type: tcp
>> >> >Bricks:
>> >> >Brick1: nexus2:/mnt/SNIP_block1/SNIP_data1
>> >> >Brick2: forge:/mnt/SNIP_block1/SNIP_data1
>> >> >Brick3: hive:/mnt/SNIP_block1/SNIP_data1
>> >> >Brick4: citadel:/mnt/SNIP_block1/SNIP_data1
>> >> >Options Reconfigured:
>> >> >cluster.quorum-count: 1
>> >> >cluster.quorum-type: fixed
>> >> >network.ping-timeout: 5
>> >> >network.remote-dio: enable
>> >> >performance.rda-cache-limit: 256MB
>> >> >performance.readdir-ahead: on
>> >> >performance.parallel-readdir: on
>> >> >network.inode-lru-limit: 500000
>> >> >performance.md-cache-timeout: 600
>> >> >performance.cache-invalidation: on
>> >> >performance.stat-prefetch: on
>> >> >features.cache-invalidation-timeout: 600
>> >> >features.cache-invalidation: on
>> >> >cluster.readdir-optimize: on
>> >> >performance.io-thread-count: 32
>> >> >server.event-threads: 4
>> >> >client.event-threads: 4
>> >> >performance.read-ahead: off
>> >> >cluster.lookup-optimize: on
>> >> >performance.cache-size: 1GB
>> >> >cluster.self-heal-daemon: enable
>> >> >transport.address-family: inet
>> >> >nfs.disable: on
>> >> >performance.client-io-threads: on
>> >> >cluster.granular-entry-heal: enable
>> >> >cluster.data-self-heal-algorithm: full
>> >> >
>> >> >Sincerely,
>> >> >Artem
>> >> >
>> >> >--
>> >> >Founder, Android Police <http://www.androidpolice.com>, APK
>Mirror
>> >> ><http://www.apkmirror.com/>, Illogical Robot LLC
>> >> >beerpla.net | @ArtemR <http://twitter.com/ArtemR>
>> >>
>> >> Hi Artem,
>> >>
>> >> Have you checked the same on brick level ? How big is the
>difference
>> >?
>> >>
>> >> Best Regards,
>> >> Strahil Nikolov
>> >>
>>
>> Hi Artem,
>>
>> My bad I missed the 'xfs' word... Still the difference  is huge.
>>
>> May I ask you to do a test again (pure curiosity) as follows:
>> 1. Repeat the test from before
>> 2. Stop 1 brick  and test again.
>>
>>
>> P.S.: You can try it on the test cluster
>>
>> Best Regards,
>> Strahil Nikolov
>>

Hi Artem,

I was wondering if the 4th replica  is adding additional overhead (another dir to check), but the test is not very conclusive.


Actually the 'anomalities' log entries in your pool  could be a symptom of another pdoblem (just like the long listing time).

I will try to reproduce your setup (smaller scale -  1  brick 50k files)  and then will try with 3 bricks.


Best Regards,
Strahil Nikolov
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