Re: Performance tuning on FreeBSD

On Mon, Mar 3, 2008 at 4:26 PM, Bill Moran
<wmoran(at)collaborativefusion(dot)com> wrote:

> > > cat /boot/loader.conf
> > kern.ipc.semmni=256
> > kern.ipc.semmns=512
> > kern.ipc.semmnu=256
> >
> > > cat /etc/sysctl.conf
> > kern.ipc.shmall=393216
> > kern.ipc.shmmax=1610612736
>
> I would just set this to 2G (which is the max). It doesn't really hurt
> anything if you don't use it all.

I'll try that and report back.

> > kern.ipc.semmap=256
> > kern.ipc.shm_use_phys=1
> >
> > postgresql.conf settings (changed from Default):
> > max_connections = 180
> > shared_buffers = 1024MB
>
> Why not 2G, which would be 25% of total memory?

Ditto - I'll report back.

> Are you running FreeBSD 7? If performance is of the utmost importance,
> then you need to be running the 7.X branch.
>
> Based on your pgbench results, I'm guessing you didn't get battery-backed
> cache on your systems? That makes a big difference no matter what OS
> you're using.
>
> Besides that, I can't think of any FreeBSD-specific things to do. Basically,
> general tuning advice applies to FreeBSD as well as to most other OS.

Yes, FreeBSD 7.0-Release. Tried both the 4BSD and ULE schedulers and
didn't see much difference with this test.
I do have the Battery for the 3ware and it is enabled. I'll do some
bonnie++ benchmarks and make sure disk is near where it should be.

Should turning off fsync make things roughly 8x-10x faster? Or is
that indicative of something not being correct or tuned quite right in
the rest of the system? I'll have to run in production with fsync on
but was just testing to see how much of an effect it had.

Thanks,
Alan