Re: Using IOZone to simulate DB access patterns

On Sat, Apr 11, 2009 at 11:44 AM, Mark Wong <markwkm(at)gmail(dot)com> wrote:
> On Fri, Apr 10, 2009 at 11:01 AM, Greg Smith <gsmith(at)gregsmith(dot)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...

FYI, I've updated the wiki with the parameters I'm running with now.
I haven't updated the results yet though.

Regards,
Mark