XFS: Abysmal write performance because of excessive seeking (allocation groups to blame?)

[Stefan Ring]

>> So 150 MB/sec seems to be the
>> best these disks can do,
>
> Definitely NOT right. I mean I've got routinely 600 MB/s from 8 7.2K
> drives RAID-6 arrays. Unless cache is off, which RAID-6 isn't obviously
> thought for.

In this case it was a 2-disk RAID 1, so it’s 150 MB/s per disk. Seems
quite right to me.