On Mon, Nov 16, 2009 at 1:04 PM, Robert Schnabel <schnabelr@missouri.edu> wrote:
>
> So the short answer is yes, I have it running with
> PostgreSQL and have not had any problems.
>
>
> Have you unplugged the power cord a few times in the middle of heavy
> write activity?
>
> ...Robert
>
> Nope. Forgive my ignorance but isn't that what a UPS is for anyway? Along
> with a BBU controller.
BBU controller, yes. UPS, no. I've seen more than one multi-million
dollar hosting center go down from something as simple as a piece of
wire flying into a power conditioner, shorting it out, and feeding
back and blowing every single power conditioner and UPS AND the switch
that allowed the diesel to come into the loop. All failed. Every
machine lost power. One database server out of a few dozens came back
up. In fact there were a lot of different dbm systems running in that
center, and only the pg 7.2 version came back up unscathed.
Because someone insisted on pulling the plug out from the back a dozen
or so times to make sure it would do come back up. PG saved our
shorts and the asses they contain. Sad thing is I'm sure the other
servers COULD have come back up if they had been running proper BBUs
and hard drives that didn't lie about fsync, and an OS that enforced
fsync properly, at least for scsi, at the time.
Power supplies / UPSes fail far more often than one might think. And
a db that doesn't come back up afterwards is not to be placed into
production.