HDD benchmarks on Linux

[Reektan]

Hi all,

I've got a HP machine here with a RAID5 + hot spare config. A friend has told me it seems to be very slow on the local disk and gave me a command to run :

"hdparm -t /dev/cciss/c0d0p3"

Running this I get :

Timing buffered disk reads: 80 MB in 3.84 seconds = 20.85 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate ioctl for device

Running the same command on another machine ( this just has 2 hdd's in RAID1 ) I get :

Timing buffered disk reads: 212 MB in 3.00 seconds = 70.67 MB/sec

Does anybody have any ideas as to why they're so different in speeds?

Thanks in advance.

 

[matja]

never used a cciss myself, but you could try playing with 'blockdev --setra' for different values - that's helped me with performance issues on adaptec aacraid cards. It was being set pretty high by default and was spending more time reading ahead than what the kernel was actually asking for.