Re: SW-RAID0 Performance problems

From: Andreas Peter (ujq7@rz.uni-karlsruhe.de)
Date: Sat Apr 14 2001 - 05:45:07 EST


Am Freitag, 13. April 2001 20:11 schrieb Tim Moore:

> Try 'hdparm -tT' with simultaneous /dev/hda3 and /dev/hdc3. This gives
> you a baseline on the actual partitions involved.

hdparm -tT simultanous on /dev/hda3 and /dev/hdc3:

/dev/hda3:
 Timing buffer-cache reads: 128 MB in 2.29 seconds = 55.90 MB/sec
 Timing buffered disk reads: 64 MB in 4.67 seconds = 13.70 MB/sec

/dev/hdc3:
 Timing buffer-cache reads: 128 MB in 2.28 seconds = 56.14 MB/sec
 Timing buffered disk reads: 64 MB in 4.61 seconds = 13.88 MB/sec

Now on single HD - /dev/hda3 :

/dev/hda3:
 Timing buffer-cache reads: 128 MB in 1.30 seconds = 98.46 MB/sec
 Timing buffered disk reads: 64 MB in 2.26 seconds = 28.32 MB/sec

It looks like reading on /dev/hda3 locks /dev/hdc3 ...
Is it necessary to apply the ide-patches to the kernel ?

Andreas

-- 
Andreas Peter *** ujq7@rz.uni-karlsruhe.de

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