Re: Using IOZone to simulate DB access patterns
Mark Wong <markwkm@gmail.com>
From: Mark Wong <markwkm@gmail.com>
To: Greg Smith <gsmith@gregsmith.com>
Cc: Scott Carey <scott@richrelevance.com>, Josh Berkus <josh@agliodbs.com>, henk de wit <henk53602@hotmail.com>, "jesper@krogh.cc" <jesper@krogh.cc>, "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>, Selena Deckelmann <selenamarie@gmail.com>, Gabrielle Roth <gorthx@gmail.com>
Date: 2009-04-27T03:28:13Z
Lists: pgsql-performance
On Sat, Apr 11, 2009 at 11:44 AM, Mark Wong <markwkm@gmail.com> wrote: > 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... FYI, I've updated the wiki with the parameters I'm running with now. I haven't updated the results yet though. Regards, Mark