[Gluster-users] Slow write times to gluster disk

[Raghavendra Gowdappa]

On Thu, Jun 21, 2018 at 10:24 AM, Raghavendra Gowdappa <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
> > wrote:
>
>>
>>
>> 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[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 <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). Specifically we were testing the suggestions in a
>>>> recent post (http://lists.gluster.org/pipe
>>>> rmail/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:  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
>>>> http://lists.gluster.org/mailman/listinfo/gluster-users
>>>
>>>
>>>
>>
>
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