disk read speed with md - normal?

disk read speed with md - normal?

Post by jw » Fri, 05 Jun 1998 04:00:00



I've just bought myself 2 IBM DDRS 4.5 Gb UW scsi-drives, and of
course the first thing to do was to test if a striped raid partition
with md would be a real screamer.

I'm not sure, in short.

My setup: AMD K6-200, BusLogic BT-956 Wide (not ultra) controller, 64
mb memory, kernel 2.0.33, md-0.35.

I appended the binary of pine to itself a few times, so as to get a
file of 425569200 bytes (405 mb).

Then I ran time cp ./pinefile /dev/null a few times on different
setups.

ibm dhea 4.3 Gb eide drive:             48 s/8.4 Mb/s  (ext2)
wd caviar 2.5 Gb eide drive:            109 s/ 3.7 Mb/s (vfat)
ibm ddrs uw scsi drive:                         44 s/ 9.2 Mb/s (just one disk,
ext2)
md raid0 4kb blocks:                            38 s/ 10.7 Mb/s (2 partitions
striped, ext2)
md raid0 64kb blocks:                           35 s/ 11.6 (idem)

The gain from md seems small. Is there anyone else with other
experiences? Did I do something wrong compiling md?

Another question: what is a good disk-speed-benchmark in Linux (a
web-page with results would be nice!)

Greetings,
Jurriaan
I haven't been so e*d since the introduction of the American style siren.
        Derek Grim - The Thin Blue Line