2.4.22 + RAID 1 + SATA + 2 disks => no maximum speed

Hi!

I have a machine with 2 SATA disks on 2 separate buses.
hdparm -t /dev/hda reports 50MB/s
hdparm -t /dev/hdb reports 50MB/s

I created a raid1 array with hda3 and hdc3, same partition sizes.

If I do hdparm -t /dev/md0 it reports 50MB/s

If I do cat /dev/md0 > /dev/null, vmstat reports 50MB/s
If I start another cat /dev/md0 > /dev/null, in another console, I get
100MB/s from vmstat.

Why I don't get 100MB/s on a single cat command?


Some other test:
cat /dev/hda3 > /dev/null&
cat /dev/hdc3 > /dev/null&
vmstat shows 100MB/s.

Also, seems that writing is very slow (8MB/s).

Any ideas?

Thank you very much!

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Catalin(ux) BOIE
catab@deuroconsult.ro