On Tue, 13 Mar 2007, Tomka Gergely wrote:
Hi!
I am currently testing 3ware raid cards. Now i have 15 disks, and on these
a swraid0. The write speed seems good (700 MBps), but the read performance
only 350 MBps. Another problem when i try to read with two process, then
the _sum_ of the read speeds fall back to 200 MBps. So there is a
bottleneck, or something i need to know, but i dont have ideas.
The details:
/dev/md0:
Version : 00.90.03
Creation Time : Tue Mar 13 16:57:32 2007
Raid Level : raid0
Array Size : 7325797440 (6986.43 GiB 7501.62 GB)
Raid Devices : 15
Total Devices : 15
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Tue Mar 13 16:57:32 2007
State : clean
Active Devices : 15
Working Devices : 15
Failed Devices : 0
Spare Devices : 0
Chunk Size : 64K
# uname -a
Linux ursula 2.6.18-4-686-bigmem #1 SMP Wed Feb 21 17:30:22 UTC 2007 i686
GNU/Linux
# xfs_info /mnt/
meta-data=/dev/md0 isize=256 agcount=32, agsize=57232784
blks
= sectsz=512 attr=0
data = bsize=4096 blocks=1831449088,
imaxpct=25
= sunit=16 swidth=240 blks, unwritten=1
naming =version 2 bsize=4096
log =internal bsize=4096 blocks=32768, version=1
= sectsz=512 sunit=0 blks
realtime =none extsz=983040 blocks=0, rtextents=0
(all software Debian Etch)
four Intel(R) Xeon(TM) CPU 3.00GHz
two 3ware 9590SE-8ML on PCIe
Intel Corporation 5000P Chipset
--
Tomka Gergely, gergely@xxxxxxxx
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Have you tried increasing your readahead values for the md device?
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