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 ??crits
268435456 bytes (268 MB) copied, 72,7446 s, 3,7 MB/s
* and without it:
~# dd if=/dev/zero of=/mnt/test_file count=262144 bs=1024
262144+0 enregistrements lus
262144+0 enregistrements ??crits
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
