[Gluster-users] Slow write times to gluster disk
rgowdapp at redhat.com
Thu Jun 21 04:54:13 UTC 2018
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.
Can you set,
# gluster volume set <volname> performance.write-behind off
and redo the tests writing to glusterfs mount? Let us know about the
results you see.
On Thu, Jun 21, 2018 at 8:33 AM, Raghavendra Gowdappa <rgowdapp at redhat.com>
> On Thu, Jun 21, 2018 at 8:32 AM, Raghavendra Gowdappa <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. 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
>  https://bugzilla.redhat.com/show_bug.cgi?id=1084508
>  https://bugzilla.redhat.com/show_bug.cgi?id=1214489
>> On Thu, Jun 21, 2018 at 5:00 AM, Pat Haley <phaley at mit.edu> wrote:
>>> We were recently revisiting our problems with the slowness of gluster
>>> writes (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). 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
>>> 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
>>> Gluster-users mailing list
>>> Gluster-users at gluster.org
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