> I have seen behavior like this in the past on EC2. I believe your
> bottleneck may be pulling the data out of cache. I benchmarked this a
> while back and found that memory speeds are not much faster than disk
> speeds on EC2. I am not sure if that is true of Xen in general or if
> its just limited to the cloud.
that doesn't make much sense.
more likely, he's disk IO bound, but hard to say as that iostat output
only showed a couple 2 second slices of work. the first output, which
shows average since system startup, seems to show the system has had
relatively high average wait times of 100ms on the average, yet the
samples below only show 0, 2, 3mS await.