shouldnt affect db performance.
On Thu, Mar 17, 2005 at 03:17:28PM +0100, Andreas Piesk
wrote:> hi list,
>
>
> i have a little problem with 2-node RAC using OCFS. the application running
> on this cluster does heavily index-based accesses. the data volumes are SAN
> volumes connected by fibrechannel.
>
> the throughput does not exceed 10mb/s, average is 7-8 mb/s. i've used
> 'iostat -x' and got rkB/s=8000 while %util=100% (device was
saturated) from
> kernel's POV.
>
>
> i did some benchmarking with Bonnie (http://www.textuality.com/bonnie/):
>
> # ./Bonnie -d /tmp/ocfstest/ -s 1024 -m bn1rac001 -o_direct -p 1
> Bonnie 1.4: File '/tmp/ocfstest/Bonnie.7166', size: 1073741824,
volumes: 1
> Using O_DIRECT for block based I/O
> Writing with putc()... done: 10816 kB/s 59.1 %CPU
> Rewriting... done: 15607 kB/s 2.2 %CPU
> Writing intelligently... done: 18442 kB/s 2.1 %CPU
> Reading with getc()... done: 20908 kB/s 60.6 %CPU
> Reading intelligently... done: 45169 kB/s 4.4 %CPU
> Seeker 1...start 'em...done...
> ---Sequential Output (nosync)--- ---Sequential Input-- --Rnd
> Seek-
> -Per Char- -DIOBlock- -DRewrite- -Per Char- -DIOBlock- --04k
> (01)-
> Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec
> %CPU
> bn1rac 1*1024 10816 59.1 18442 2.1 15607 2.2 20908 60.6 45169 4.4 11.3
> 0.4
>
>
> # ./Bonnie -d /root/ext3test/ -s 1024 -m bn1rac001 -o_direct -p 1
> Bonnie 1.4: File '/tmp/ext3test/Bonnie.7843', size: 1073741824,
volumes: 1
> Using O_DIRECT for block based I/O
> Writing with putc()... done: 28471 kB/s 91.6 %CPU
> Rewriting... done: 15014 kB/s 5.1 %CPU
> Writing intelligently... done: 23810 kB/s 7.0 %CPU
> Reading with getc()... done: 13150 kB/s 42.8 %CPU
> Reading intelligently... done: 42893 kB/s 3.6 %CPU
> Seeker 1...start 'em...done...
> ---Sequential Output (nosync)--- ---Sequential Input-- --Rnd
> Seek-
> -Per Char- -DIOBlock- -DRewrite- -Per Char- -DIOBlock- --04k
> (01)-
> Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec
> %CPU
> bn1rac 1*1024 28471 91.6 23810 7.0 15014 5.1 13150 42.8 42893 3.6 182.4
> 1.8
>
>
> the first run is on ocfs, the second an ext3. both runs used
'O_DIRECT'.
> the directory '/tmp' is on a local hard disk (takes the SAN out of
the
> game).
> the overall performance is not too bad. writing on ocfs is somewhat slower
> but reading is faster.
> the random seeks are worst, 11.3 vs. 182.4 /s. i'm not sure what's
the
> reason. Bonnie uses lseek(2) to perform the seek operation.
>
> maybe this seek-problem is the reason for the insufficient read performance
> of 8mb/s on index-bases access? is this type of benchmark valid for ocfs?
> if yes, can someone could repeat it to verify the results?
>
> thanks for reading.
>
>
> Best,
>
> -ap
>
> --
> Andreas Piesk
> Systemadministration E-/M-Commerce
> --------------------------------------------------------------
> V?B-ZVD
> Bank f?r Zahlungsverkehrsdienstleistungen GmbH
> Godesberger Allee 88
>
> 53175 Bonn
>
> Tel.: +49 (0) 228 9377-535
> Fax: +49 (0) 228 9377-596
> E-Mail: andreas.piesk@voeb-zvd.de
> Internet: http://www.voeb-zvd.de
>
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