[kwlug-disc] MDADM and RAID

Chris Irwin chris at chrisirwin.ca
Wed Mar 3 20:20:52 EST 2010


In deciding whether to make separate fast and slow RAID1 arrays, I
decided to check read speeds. I did the same 5.2GB test for writing, but
of=/dev/null.

> sda2: 38.0 MB/s for a time of 2m17.913.

85.4 MB/s in 1m1.380. This is a Hitachi with 16MB cache.

> sdb2: 108 MB/s for a time of 0m50.240.

116 MB/s in 0m45.320. This is the Seagate with 32MB cache.

CPU utilization hit 70% on read for the Hitachi disks, and 55% for the
Seagates. So let that be a lesson to everybody: Disk cache matters.

-- 
Chris Irwin
e:  chris at chrisirwin.ca
w: http://chrisirwin.ca
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: This is a digitally signed message part
URL: <http://astoria.ccjclearline.com/pipermail/kwlug-disc_kwlug.org/attachments/20100303/141cd512/attachment.bin>


More information about the kwlug-disc_kwlug.org mailing list