extremly slow random read on new raid5 array
I just setup a new md raid5 array with 4 Seagate 7200.12 1TB disks. The sequential read and write is pretty amazing to me, but the random read is going very slowly. iostat says its going at about 500KB/s vs the 300MB/s+ and 170MB/s+ for sequential read and write respectively.
I've seen people report they get random reads in the double digit MB range, and I would have at least liked to see 50MB/s or something along those lines. The raid array is setup with a 64KB chunk, I'm using ext4 (the mkfs and fsck times for the full array with ext3 would have killed me, and I'm starting to dislike the occasional corruption and slowness I get with XFS). What am I missing? There's got to be something I misconfigured some place. |
My iozone test finished, so I'll post the results:
Code:
natasha:/mnt/test-data# time iozone -a -s 8G |
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