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SubjectTuning Linux for high-speed disk subsystems
Hi all

After some testing at Compaq's lab in Oslo, I've come to the conclusion
that Linux cannot scale higher than about 30-40MB/sec in or out of a
hardware or software RAID-0 set with several stripe/chunk sizes tried out.
The set is based on 5 18GB 10k disks running SCSI-3 (160MBps) alone on a
32bit/33MHz PCI bus.

After speking to the storage guys here, I was told the problem generally
was that the OS should send the data requests at 256kB block sizes, as the
drives (10k) could handle 100 I/O operations per second, and thereby could
give a total of (256*100)kB/sec per spindle. When using smaller block
sizes, the speed would decrease in a linear fasion.

Does anyone know this stuff good enough to help me how to tune the system?
PS: The CPUs were almost idle during the test. Tested file system was
ext2.

Regards

roy

--
Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA

Computers are like air conditioners.
They stop working when you open Windows.


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