complain about dpt_2o driver and CPU time
Dear Deanna and others,
I am using the ASR2100 RAID card and running 2.4.17 Linux . It seems the card is very slow in RAID5 computation. I use 5x18GB 10,000rpm seagate drives. The card orginal comes with a 32MB ECC SD RAM as cache buffer. I feel that the card is very slow, the test with Bonnie shows 1810KB/sec with CPU load less than 2%. This shows the CPU time is idle, but the load average go up to around 13-14 . This means the dpt_i2o driver is probably not written very good in releasing the cpu time (call to schedule()) on blocking calls, probably in some IO waiting routines(I am not sure), or it is holding some big locks in a slow place. The CPU is sitting there doing nothing, but this behaviour always block my NFS clients ("server not responding, still trying") and the machine looks like dead not even response to a console keyboard input. Can you tell me about what is going on or who else is suffering from the same result? I would like to do some improvement of the driver, or the card is really that slow? My 10year old SCSI drive (no raid) runs 2200Kb/sec and is even faster than this Ultra-160 SCSI i960 RAID with 32MB cache. If this is the case, I will just throw it away and use my onboard Ultra-160 connector with software RAID which runs faster(at least). This is almost unusable for even small workgroup server.
regards,
David
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feel that the card is very slow, the test with Bonnie shows 1810KB/sec with CPU load less than 2%. This shows the CPU time is idle, but the load average go up to around 13-14 . This means the
dpt_i2odriver is
The load average includes I/O waiting. So that may well mean you have 14 different processes waiting for the card.
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even faster than this Ultra-160 SCSI i960 RAID with 32MB cache. If this is the case, I will just throw it away and use my onboard Ultra-160 connector with software RAID which runs faster(at least). This is almost unusable for even small workgroup server.
The numbers seem extremely poor. There are plenty of abysmally slow RAID controllers out there but I'd expect bettere than 1810K/second even on things like old Megaraid cards.
Alan