Hi
You are using a partition. Is it correctly aligned? Usually the first
partition starts at sector 63. Which is in the middle of your stripe.
Use the whole disk (/dev/sda) or align the start of the partition to a
multiple of the stripe size.
But i doubt you will see a performance improvement with such a simple
test (single threaded sequential read/ write).
utz
On Fri, 2006-08-11 at 23:10 -0400, Brian Davis wrote:
> Is this expected? I thought I would see more improvement when tweaking
> my su/sw values for hardware RAID 5.
>
> Details, 3x300GB drives, 3Ware 7506-4LP Hardware RAID 5 using a 64K
> stripe size (non-configurable on this card).
>
> FS creation and Bonnie++ results:
>
> Untweaked:----------------------------------------------------------------------
>
>
>
> localhost / # mkfs.xfs -f /dev/sda1
> meta-data=/dev/sda1 isize=256 agcount=32, agsize=4578999
> blks
> = sectsz=512 attr=0
> data = bsize=4096 blocks=146527968, imaxpct=25
> = sunit=0 swidth=0 blks, unwritten=1
> naming =version 2 bsize=4096
> log =internal log bsize=4096 blocks=32768, version=1
> = sectsz=512 sunit=0 blks
> realtime =none extsz=65536 blocks=0, rtextents=0
> localhost / # mount -t xfs /dev/sda1 /raid
> localhost / # cd /raid
> localhost raid # bonnie++ -n0 -u0 -r 768 -s 30720 -b -f
> Using uid:0, gid:0.
> Writing intelligently...done
> Rewriting...done
> Reading intelligently...done
> start 'em...done...done...done...done...done...
> Version 1.93c ------Sequential Output------ --Sequential Input-
> --Random-
> Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
> --Seeks--
> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
> /sec %CP
> localhost 30G 27722 40 23847 37 98367 99
> 88.6 11
> Latency 891ms 693ms 16968us
> 334ms
>
> Tweaked:-------------------------------------------------------------------------
>
>
>
> localhost / # mkfs.xfs -f -d sw=2,su=64k /dev/sda1
> meta-data=/dev/sda1 isize=256 agcount=32, agsize=4578992
> blks
> = sectsz=512 attr=0
> data = bsize=4096 blocks=146527744, imaxpct=25
> = sunit=16 swidth=32 blks, unwritten=1
> naming =version 2 bsize=4096
> log =internal log bsize=4096 blocks=32768, version=1
> = sectsz=512 sunit=0 blks
> realtime =none extsz=65536 blocks=0, rtextents=0
> localhost / # mount -t xfs /dev/sda1 /raid
> localhost / # cd /raid
> localhost raid # bonnie++ -n0 -u0 -r 768 -s 30720 -b -f
> Using uid:0, gid:0.
> Writing intelligently...done
> Rewriting...done
> Reading intelligently...done
> start 'em...done...done...done...done...done...
> Version 1.93c ------Sequential Output------ --Sequential Input-
> --Random-
> Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
> --Seeks--
> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
> /sec %CP
> localhost 30G 27938 43 23880 40 98066 99
> 91.8 9
> Latency 772ms 584ms 19889us
> 340ms
>
--
<> utz lehmann
<> <> u.lehmann@xxxxxxxxxxxxxx
<> <> <> TECOSIM GmbH / IT
<> <> +49(0)-6142-82720
<> http://www.tecosim.com/
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