pgtune and massive shared_buffers recommendation

Hi.

I've got some boxes with 128GB of RAM and up to 750 connections, just
upgraded to 9.3 so I'm revising my tuning. I'm getting a
recommendation from pgtune to bump my shared_buffers up to 30GB and
work_mem to 80MB. Is a shared_buffers this high now sane?

The PostgreSQL reference doesn't make recommendations on limits, but
it didn't either with earlier versions of PostgreSQL where more than a
few GB was normally a bad thing to do. The most recent blob posts I
see mentioning 9.3 and modern RAM sizes still seem to cap it at 8GB.

(and yes, I am using pgbouncer but stuck in session mode and up to 750
connections for the time being)

--
Stuart Bishop <stuart(at)stuartbishop(dot)net>
http://www.stuartbishop.net/