Re: SSD + RAID

On Wed, Nov 18, 2009 at 11:39 PM, Scott Carey  wrote:
> Well, that is sort of true for all benchmarks, but I do find that bonnie++
> is the worst of the bunch.  I consider it relatively useless compared to
> fio.  Its just not a great benchmark for server type load and I find it
> lacking in the ability to simulate real applications.

I agree.   My biggest gripe with bonnie actually is that 99% of the
time is spent measuring in sequential tests which is not that
important in the database world.  Dedicated wal volume uses ostensibly
sequential io, but it's fairly difficult to outrun a dedicated wal
volume even if it's on a vanilla sata drive.

pgbench is actually a pretty awesome i/o tester assuming you have big
enough scaling factor, because:
a) it's much closer to the environment you will actually run in
b) you get to see what i/o affecting options have on the load
c) you have broad array of options regarding what gets done (select
only, -f, etc)
d) once you build the test database, you can do multiple runs without
rebuilding it

merlin

merlin