[Gluster-users] AFR performance killer

[Raghavendra G]

Hi Marko,

The option disable-for-first-nbytes disables write behind for the first n
bytes written, where n is the value of the option.

Also, Can you please send the benmark results for the tests you carried out?

regards,
On Wed, Apr 8, 2009 at 6:18 PM, Marko <gluster at sopca.com> wrote:

> Hello,
>
> To clearify:
>  * im testing with gluisterfs-2.0.0rc7
>  * all bricks are on same physical server(Xen guests). It's a testing
> environment.
>
> These are a few benchmarks I've done so far:
>   * time make-many-files #(this is slightly modified version that I've
> found here:http://www.linuxinsight.com/files/make-many-files.c)
>   * time dd if=/dev/zero bs=8 count=128000 of=file1MB.bin #(effectively
> creates lots of small consecutive fops)
>   * time dd if=/dev/zero bs=4096 count=25000  of=file100MB.bin #(creates
> optimal transactions from HDDs physical point of  view. I have best results
> here with all configurations)
>   * time cp -a 0 1 2 /tmp #(/tmp is mounted as tmpfs; 0 1 2 are directories
> created by "make-many-files" )
>   * time rm 0 1 2 -fr
>
> I wish GlusterFS team provided simmilar set of tests so one can measure his
> performance in a way that can be compared to results from others. I think it
> would be a great value to all GlusterFS users and developers. I think that
> to create basic set of these tests is a trivial task( maybe just use mine :D
> ).
>
> Below I attached my configuration.  Without write-back translator I get
> better results in most of the tests.
> I can't understand why write-back has such a bad impact on
> performance(being a performance *booster*).
> I've also noticed that TCP packets are  much lower than MTU in first
> benchmark. Meaning write-back doesn't optimize writes.
> Can you explain that?
> Can someone help me to get high performance with AFR?
>
> Regards,
> Marko
>
>
> #------------- configuration ---------------------
> ########## server ###########################
> volume posix-brick
>  type storage/posix
>  option directory /srv/gluster
> end-volume
>
> volume lock-brick
>  type features/posix-locks
>  subvolumes posix-brick
>  option mandatory-locks on
> end-volume
>
> volume server
>       type protocol/server
>       option transport-type tcp/server
>       subvolumes lock-brick
>       option auth.addr.lock-brick.allow *
> end-volume
>
>
>
> ########## client ###########################
>
> volume brick1
> type protocol/client
> option transport-type tcp
> option remote-host gluster-host1
> option remote-subvolume lock-brick
> end-volume
>
> volume brick2
> type protocol/client
> option transport-type tcp
> option remote-host gluster-host2
> option remote-subvolume lock-brick
> end-volume
>
> volume AFR
> type cluster/replicate
> subvolumes brick1 brick2
> end-volume
>
> volume wb
>  type performance/write-behind
>  subvolumes AFR
>  option flush-behind on
>  option window-size 1MB
>  option aggregate-size 512KB
> end-volume
>
>
>
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>



-- 
Raghavendra G
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