Re: which dual-CPU hardware/OS is fastest for PostgreSQL?

Josh Berkus <josh@agliodbs.com> writes:

> Merlin,
>
> > I think the danger about SATA is that many SATA components are not
> > server quality, so you have to be more careful about what you buy.  For
> > example, you can't just assume your SATA backplane has hot swap lights
> > (got bit by this one myself, heh).
>
> Yeah, that's my big problem with anything IDE.    My personal experience of
> failure rates for IDE drives, for example, is about 1 out of 10 fails in
> service before it's a year old; SCSI has been more like 1 out of 50.

Um. I'm pretty sure the actual hardware is just the same stuff. It's just the
interface electronics that change.

> Also, while I've seen benchmarks like Escalade's, my real-world experience has
> been that the full bi-directional r/w of SCSI means that it takes 2 SATA
> drives to equal one SCSI drive in a heavy r/w application.   However, ODSL is
> all SCSI so I don't have any numbers to back that up.

Do we know that these SATA/IDE controllers and drives don't "lie" about fsync
the way most IDE drives do? Does the controller just automatically disable the
write caching entirely?

I don't recall, did someone have a program that tested the write latency of a
drive to test this?

--
greg