RAID0: performance oddity (2.2.0pre7)

Chris Evans (chris@ferret.lmh.ox.ac.uk)
Sun, 17 Jan 1999 18:52:35 +0000 (GMT)


Hi,

I have a raid0 array of 2 disks, both of which can do ~6.5Mb/sec.

With chunksize = 4k (default), the md0 device can shift ~11.5Mb/sec. Not
bad.

However bumping up the chunksize to 64k _decreases_ performance on the
array to ~6Mb/sec. This is slower than either individual disk!

I would have thought increasing chunksize would increase performance due
to decreased overhead?

Performance measurements are taken using "hdparm"

Cheers
Chris

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