On Fri, Apr 10, 2009 at 11:01 AM, Greg Smith <gsmith@gregsmith.com> wrote:
> On Fri, 10 Apr 2009, Scott Carey wrote:
>
>> FIO with profiles such as the below samples are easy to set up
>
> There are some more sample FIO profiles with results from various
> filesystems at
> http://wiki.postgresql.org/wiki/HP_ProLiant_DL380_G5_Tuning_Guide
There's a couple of potential flaws I'm trying to characterize this
weekend. I'm having second thoughts about how I did the sequential
read and write profiles. Using multiple processes doesn't let it
really do sequential i/o. I've done one comparison so far resulting
in about 50% more throughput using just one process to do sequential
writes. I just want to make sure there shouldn't be any concern for
being processor bound on one core.
The other flaw is having a minimum run time. The max of 1 hour seems
to be good to establishing steady system utilization, but letting some
tests finish in less than 15 minutes doesn't provide "good" data.
"Good" meaning looking at the time series of data and feeling
confident it's a reliable result. I think I'm describing that
correctly...
Regards,
Mark
