[Gluster-users] Slow write times to gluster disk

Pat Haley phaley at mit.edu
Fri Jun 29 17:08:41 UTC 2018


Hi Raghavendra,

We ran the tests (write tests) and I copied the log files for both the 
server and the client to 
http://mseas.mit.edu/download/phaley/GlusterUsers/2018/Jun29/ .  Is 
there any additional trace information you need?  (If so, where should I 
look for it?)

Also the volume information you requested

[root at mseas-data2 ~]# gluster volume info data-volume

Volume Name: data-volume
Type: Distribute
Volume ID: c162161e-2a2d-4dac-b015-f31fd89ceb18
Status: Started
Number of Bricks: 2
Transport-type: tcp
Bricks:
Brick1: mseas-data2:/mnt/brick1
Brick2: mseas-data2:/mnt/brick2
Options Reconfigured:
diagnostics.client-log-level: TRACE
network.inode-lru-limit: 50000
performance.md-cache-timeout: 60
performance.open-behind: off
disperse.eager-lock: off
auth.allow: *
server.allow-insecure: on
nfs.exports-auth-enable: on
diagnostics.brick-sys-log-level: WARNING
performance.readdir-ahead: on
nfs.disable: on
nfs.export-volumes: off
[root at mseas-data2 ~]#


On 06/29/2018 12:28 PM, Raghavendra Gowdappa wrote:
>
>
> On Fri, Jun 29, 2018 at 8:24 PM, Pat Haley <phaley at mit.edu 
> <mailto:phaley at mit.edu>> wrote:
>
>
>     Hi Raghavendra,
>
>     Our technician was able to try the manual setting today.  He found
>     that our upper limit for performance.md-cache-timeout was 60 not
>     600, so he used that value, along with the
>     network.inode-lru-limit=50000.
>
>     The result was another small (~1%) increase in speed. Does this
>     suggest some addition tests/changes we could try?
>
>
> Can you set gluster option diagnostics.client-log-level to TRACE  and 
> run sequential read tests again (with md-cache-timeout value of 60)?
>
> #gluster volume set <volname> diagnostics.client-log-level TRACE
>
> Also are you sure that open-behind was turned off? Can you give the 
> output of,
>
> # gluster volume info <volname>
>
>
>     Thanks
>
>     Pat
>
>
>
>
>     On 06/25/2018 09:39 PM, Raghavendra Gowdappa wrote:
>>
>>
>>     On Tue, Jun 26, 2018 at 3:21 AM, Pat Haley <phaley at mit.edu
>>     <mailto:phaley at mit.edu>> wrote:
>>
>>
>>         Hi Raghavendra,
>>
>>         Setting the performance.write-behind off had a small
>>         improvement on the write speed (~3%),
>>
>>         We were unable to turn on "group metadata-cache".  When we
>>         try get errors like
>>
>>         # gluster volume set data-volume group metadata-cache
>>         '/var/lib/glusterd/groups/metadata-cache' file format not valid.
>>
>>         Was metadata-cache available for gluster 3.7.11? We ask
>>         because the release notes for 3.11 mentions “Feature for
>>         metadata-caching/small file performance is production ready.”
>>         (https://gluster.readthedocs.io/en/latest/release-notes/3.11.0/
>>         <https://gluster.readthedocs.io/en/latest/release-notes/3.11.0/>).
>>
>>         Do any of these results suggest anything?  If not, what
>>         further tests would be useful?
>>
>>
>>     Group metadata-cache is just a bunch of options one sets on a
>>     volume. So, You can set them manually using gluster cli.
>>     Following are the options and their values:
>>
>>     performance.md-cache-timeout=600
>>     network.inode-lru-limit=50000
>>
>>
>>
>>         Thanks
>>
>>         Pat
>>
>>
>>
>>
>>         On 06/22/2018 07:51 AM, Raghavendra Gowdappa wrote:
>>>
>>>
>>>         On Thu, Jun 21, 2018 at 8:41 PM, Pat Haley <phaley at mit.edu
>>>         <mailto:phaley at mit.edu>> wrote:
>>>
>>>
>>>             Hi Raghavendra,
>>>
>>>             Thanks for the suggestions.  Our technician will be in
>>>             on Monday.  We'll test then and let you know the results.
>>>
>>>             One question I have, is the "group metadata-cache"
>>>             option supposed to directly impact the performance or is
>>>             it to help collect data?  If the latter, where will the
>>>             data be located?
>>>
>>>
>>>         It impacts performance.
>>>
>>>
>>>             Thanks again.
>>>
>>>             Pat
>>>
>>>
>>>
>>>             On 06/21/2018 01:01 AM, Raghavendra Gowdappa wrote:
>>>>
>>>>
>>>>             On Thu, Jun 21, 2018 at 10:24 AM, Raghavendra Gowdappa
>>>>             <rgowdapp at redhat.com <mailto:rgowdapp at redhat.com>> wrote:
>>>>
>>>>                 For the case of writes to glusterfs mount,
>>>>
>>>>                 I saw in earlier conversations that there are too
>>>>                 many lookups, but small number of writes. Since
>>>>                 writes cached in write-behind would invalidate
>>>>                 metadata cache, lookups won't be absorbed by
>>>>                 md-cache. I am wondering what would results look
>>>>                 like if we turn off performance.write-behind.
>>>>
>>>>                 @Pat,
>>>>
>>>>                 Can you set,
>>>>
>>>>                 # gluster volume set <volname>
>>>>                 performance.write-behind off
>>>>
>>>>
>>>>             Please turn on "group metadata-cache" for write tests too.
>>>>
>>>>
>>>>                 and redo the tests writing to glusterfs mount? Let
>>>>                 us know about the results you see.
>>>>
>>>>                 regards,
>>>>                 Raghavendra
>>>>
>>>>                 On Thu, Jun 21, 2018 at 8:33 AM, Raghavendra
>>>>                 Gowdappa <rgowdapp at redhat.com
>>>>                 <mailto:rgowdapp at redhat.com>> wrote:
>>>>
>>>>
>>>>
>>>>                     On Thu, Jun 21, 2018 at 8:32 AM, Raghavendra
>>>>                     Gowdappa <rgowdapp at redhat.com
>>>>                     <mailto:rgowdapp at redhat.com>> wrote:
>>>>
>>>>                         For the case of reading from Glusterfs
>>>>                         mount, read-ahead should help. However,
>>>>                         we've known issues with read-ahead[1][2].
>>>>                         To work around these, can you try with,
>>>>
>>>>                         1. Turn off performance.open-behind
>>>>                         #gluster volume set <volname>
>>>>                         performance.open-behind off
>>>>
>>>>                         2. enable group meta metadata-cache
>>>>                         # gluster volume set <volname> group
>>>>                         metadata-cache
>>>>
>>>>
>>>>                     [1]
>>>>                     https://bugzilla.redhat.com/show_bug.cgi?id=1084508
>>>>                     <https://bugzilla.redhat.com/show_bug.cgi?id=1084508>
>>>>                     [2]
>>>>                     https://bugzilla.redhat.com/show_bug.cgi?id=1214489
>>>>                     <https://bugzilla.redhat.com/show_bug.cgi?id=1214489>
>>>>
>>>>
>>>>
>>>>
>>>>                         On Thu, Jun 21, 2018 at 5:00 AM, Pat Haley
>>>>                         <phaley at mit.edu <mailto:phaley at mit.edu>> wrote:
>>>>
>>>>
>>>>                             Hi,
>>>>
>>>>                             We were recently revisiting our
>>>>                             problems with the slowness of gluster
>>>>                             writes
>>>>                             (http://lists.gluster.org/pipermail/gluster-users/2017-April/030529.html
>>>>                             <http://lists.gluster.org/pipermail/gluster-users/2017-April/030529.html>).
>>>>                             Specifically we were testing the
>>>>                             suggestions in a recent post
>>>>                             (http://lists.gluster.org/pipermail/gluster-users/2018-March/033699.html
>>>>                             <http://lists.gluster.org/pipermail/gluster-users/2018-March/033699.html>).
>>>>                             The first two suggestions (specifying a
>>>>                             negative-timeout in the mount settings
>>>>                             or adding rpc-auth-allow-insecure to
>>>>                             glusterd.vol) did not improve our
>>>>                             performance, while setting
>>>>                             "disperse.eager-lock off" provided a
>>>>                             tiny (5%) speed-up.
>>>>
>>>>                             Some of the various tests we have tried
>>>>                             earlier can be seen in the links below.
>>>>                             Do any of the above observations
>>>>                             suggest what we could try next to
>>>>                             either improve the speed or debug the
>>>>                             issue? Thanks
>>>>
>>>>                             http://lists.gluster.org/pipermail/gluster-users/2017-June/031565.html
>>>>                             <http://lists.gluster.org/pipermail/gluster-users/2017-June/031565.html>
>>>>                             http://lists.gluster.org/pipermail/gluster-users/2017-May/030937.html
>>>>                             <http://lists.gluster.org/pipermail/gluster-users/2017-May/030937.html>
>>>>
>>>>                             Pat
>>>>
>>>>                             -- 
>>>>
>>>>                             -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>>                             Pat Haley       Email: phaley at mit.edu
>>>>                             <mailto:phaley at mit.edu>
>>>>                             Center for Ocean Engineering    Phone:
>>>>                             (617) 253-6824
>>>>                             Dept. of Mechanical Engineering Fax:   
>>>>                             (617) 253-8125
>>>>                             MIT, Room 5-213
>>>>                             http://web.mit.edu/phaley/www/
>>>>                             77 Massachusetts Avenue
>>>>                             Cambridge, MA 02139-4301
>>>>
>>>>                             _______________________________________________
>>>>                             Gluster-users mailing list
>>>>                             Gluster-users at gluster.org
>>>>                             <mailto:Gluster-users at gluster.org>
>>>>                             http://lists.gluster.org/mailman/listinfo/gluster-users
>>>>                             <http://lists.gluster.org/mailman/listinfo/gluster-users>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>             -- 
>>>
>>>             -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>>             Pat Haley                          Email:phaley at mit.edu <mailto:phaley at mit.edu>
>>>             Center for Ocean Engineering       Phone:  (617) 253-6824
>>>             Dept. of Mechanical Engineering    Fax:    (617) 253-8125
>>>             MIT, Room 5-213http://web.mit.edu/phaley/www/
>>>             77 Massachusetts Avenue
>>>             Cambridge, MA  02139-4301
>>>
>>>
>>>             _______________________________________________
>>>             Gluster-users mailing list
>>>             Gluster-users at gluster.org <mailto:Gluster-users at gluster.org>
>>>             http://lists.gluster.org/mailman/listinfo/gluster-users
>>>             <http://lists.gluster.org/mailman/listinfo/gluster-users>
>>>
>>>
>>
>>         -- 
>>
>>         -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>>         Pat Haley                          Email:phaley at mit.edu <mailto:phaley at mit.edu>
>>         Center for Ocean Engineering       Phone:  (617) 253-6824
>>         Dept. of Mechanical Engineering    Fax:    (617) 253-8125
>>         MIT, Room 5-213http://web.mit.edu/phaley/www/
>>         77 Massachusetts Avenue
>>         Cambridge, MA  02139-4301
>>
>>
>
>     -- 
>
>     -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>     Pat Haley                          Email:phaley at mit.edu <mailto:phaley at mit.edu>
>     Center for Ocean Engineering       Phone:  (617) 253-6824
>     Dept. of Mechanical Engineering    Fax:    (617) 253-8125
>     MIT, Room 5-213http://web.mit.edu/phaley/www/
>     77 Massachusetts Avenue
>     Cambridge, MA  02139-4301
>
>

-- 

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Pat Haley                          Email:  phaley at mit.edu
Center for Ocean Engineering       Phone:  (617) 253-6824
Dept. of Mechanical Engineering    Fax:    (617) 253-8125
MIT, Room 5-213                    http://web.mit.edu/phaley/www/
77 Massachusetts Avenue
Cambridge, MA  02139-4301

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