Hi,
I've posted about performance problems with my RAID0 setup.
RAID works fine, but it's too slow.
But now it seems not to be a problem with the md code, it's an ide problem.
There are two HDs in my PC: /dev/hda and /dev/hdc. No other devices are
attached to the ide-bus.
PC is a SMP-System, 2 Celeron 533, Gigabyte 6BXDS with Intel BX-Chipset,
66MHz FSB.
The hdparm settings:
bash-2.04# hdparm /dev/hda /dev/hdc
/dev/hda:
multcount = 0 (off)
I/O support = 3 (32-bit w/sync)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 59556/16/63, sectors = 60032448, start = 0
/dev/hdc:
multcount = 0 (off)
I/O support = 3 (32-bit w/sync)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 0 (off)
geometry = 59556/16/63, sectors = 60032448, start = 0
I've tested a lot of variations of this settings (multcount=16,
unmaskirq=0...) without succes.
The performance of the RAID doesn't increase :-(
hdparm -tT on a single HD (dev/hda3 is the RAID-partition) reports a very
good performance:
bash-2.04# hdparm -tT /dev/hda3
/dev/hda3:
Timing buffer-cache reads: 128 MB in 1.42 seconds = 90.14 MB/sec
Timing buffered disk reads: 64 MB in 2.27 seconds = 28.19 MB/sec
But if I start 2 hdparms simultanous (one on /dev/hda3 the other on
/dev/hdc3) the performance on the HDs decreases to 1/2 of the original speed:
bash-2.04# hdparm -tT /dev/hda3
/dev/hda3:
Timing buffer-cache reads: 128 MB in 2.27 seconds = 56.39 MB/sec
Timing buffered disk reads: 64 MB in 4.56 seconds = 14.04 MB/sec
bash-2.04# hdparm -tT /dev/hdc3
/dev/hdc3:
Timing buffer-cache reads: 128 MB in 2.25 seconds = 56.89 MB/sec
Timing buffered disk reads: 64 MB in 4.49 seconds = 14.25 MB/sec
The performance of the RAID0:
bash-2.04# hdparm -tT /dev/md0
/dev/md0:
Timing buffer-cache reads: 128 MB in 1.35 seconds = 94.81 MB/sec
Timing buffered disk reads: 64 MB in 3.11 seconds = 20.58 MB/sec
Tests with bonnie or iozone have the same reuslts, RAID is slower then a
single HD :-(
Does anybody has an idea what's wrong with my setup??
Thx,
Andreas
--
Andreas Peter *** [EMAIL PROTECTED]
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