On 4/10/09 11:01 AM, "Greg Smith" <gsmith@xxxxxxxxxxxxx> 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 I wish to thank Greg here as many of my profile variations came from the above as a starting point. Note in his results the XFS file system behavior on random writes is due to FIO doing 'sparse writes' (which Postgres does not do, and fio exposes some issues on xfs with) in the default random write mode. To properly simulate Postgres these should be random overwrites. Add 'overwrite=true' to the profile for random writes and the whole file will be allocated before randomly (over)writing to it. Here is the man page: http://linux.die.net/man/1/fio > > -- > * Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
