> That's kind of my point. :) That 14GB isn't allocated to cache, buffers,
> any process, or anything else. It's just... free. In the middle of the
> day, where 800 PG threads are pulling 7000TPS on average. Based on that
> scenario, I'd like to think it would cache pretty aggressively, but
> instead, it's just leaving 14GB around to do absolutely nothing.
>
> It makes me sad. :(
Yeah, this is why I want to go to Linux Plumbers this year. The
Kernel.org engineers are increasingly doing things which makes Linux
unsuitable for applications which depend on the filesystem. There is a
good, but sad, reason for this: IBM and Oracle and their partners are
the largest employers of people hacking on core Linux memory/IO
functionality, and both of those companies use DirectIO extensively in
their products.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com
