On 12/08/10 23:02, Mattias Lindgren wrote:
I have 8 Seagate SATA disks connected to an intel branded LSI 3081E SAS controller (Intel SASUC8I). I have 4 of the 1.5T disks and I have 4 2T disks (both are the LP 5900RPM variety) in a pair of raidz1s in a ZFS pool. Doing simple dd writes and reads I get about 80MByte write and 150MByte read which seems very very slow to me. I'm also getting errors from mpt on boot:
Such large difference between read and write, together with the slow rotation speed of your drives could indicate that you have 4K sector drive. Can you confirm this? (report what "diskinfo -v <drive>" outputs, but you'll probably also have to lookup on the drives themselves or on the net for the specific model you have).
If so, until FreeBSD gets this right (heh), you will have to do this dance with your drives to make ZFS 4K-aligned. But first, try figuring out if the drives are 4K.
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