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 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 <[email protected]> wrote: > > > On Thu, Jun 21, 2018 at 8:32 AM, Raghavendra Gowdappa <[email protected] > > 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 > [2] https://bugzilla.redhat.com/show_bug.cgi?id=1214489 > > >> >> >> On Thu, Jun 21, 2018 at 5:00 AM, Pat Haley <[email protected]> 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). 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 >>> >>> http://lists.gluster.org/pipermail/gluster-users/2017-June/031565.html >>> http://lists.gluster.org/pipermail/gluster-users/2017-May/030937.html >>> >>> Pat >>> >>> -- >>> >>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>> Pat Haley Email: [email protected] >>> 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 >>> [email protected] >>> http://lists.gluster.org/mailman/listinfo/gluster-users >> >> >> >
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