[Gluster-users] Strange performance issues on Debian/Lenny compared to Ubuntu

[Raghavendra G]

On Thu, Apr 1, 2010 at 4:18 PM, Olivier Le Cam <
Olivier.LeCam at crdp.ac-versailles.fr> wrote:

> Hi -
>
> Thank you Raghavendra for detailed reply and information.
>
>
> Raghavendra G wrote:
>
>> I am seeing write-behind aggregating large number of writes into a single
>> large write on Ubuntu client, but not on lenny client. This is the cause
>> of
>> large number of frames on network. This can also be the cause of slower
>> performance on lenny.
>>
>> Can you set "option enable-trickling-writes false" in write-behind on
>> lenny
>> and rerun tests. That will set write-behind to do more aggressive
>> aggregation. We are eagerly waiting for your results :).
>>
>
> This is just a bit better with this option disabled:
>
> * with "option enable-trickling-writes false":
>
>    ~# dd if=/dev/zero of=/mnt/test_file count=262144 bs=1024
>    262144+0 enregistrements lus
>    262144+0 enregistrements écrits
>    268435456 bytes (268 MB) copied, 72,7446 s, 3,7 MB/s
>
>
Can you send glusterfs client logs with trace loaded above and below
write-behind?


> * and without it:
>
>    ~# dd if=/dev/zero of=/mnt/test_file count=262144 bs=1024
>    262144+0 enregistrements lus
>    262144+0 enregistrements écrits
>    268435456 bytes (268 MB) copied, 87,8484 s, 3,1 MB/s
>
> (each test repeated several times with very little variances: +/- 0.1
> MB/s).
>
> BTW, did you see the comparative results I have posted, using Deban/Lenny
> on the same hardware but with either a 2.6.18 and 2.6.26 vernel version? It
> seems that kernel version is very critical in the way write-behind is able
> to do large aggregation.
>
>
>  However I am still investigating what is the reason behind write-behind on
>> Ubuntu doing large aggregation but not on lenny.
>>
>
> Thank's a lot! I guess many people will appreciate!
>
> Kind regards,
> --
> Olivier
>



-- 
Raghavendra G