Problems setting shared_buffers to large value

Hi all,

I am running postgres 7.4.2 on a Dual processor Opteron with 16GB of ram. I
want to set shared_buffers to a large value, but I am running into startup
problems.

I have set my kernel SHMMAX and SHMALL to 12GB.

When I set shared_buffers to a value which puts the total shared memory
usage over 1GB, my postgres server fails to start. Unfortunatly, I also
cannot seem to get any logfile output out of my system (perhaps another
question).

Are there any hardcoded max values for shared_buffers? I noticed in the code
that a uint32 is used for the page size which would mean a 4GB max. This is
failing at much lower values.

Sorry that I do not have a logfile output. Perhaps someone could help me
turn my logfile on. I am passing -l logfile at startup, but my logfile
remains empty.

Thanks in advance

Barry

(barry(at)GeipelNet(dot)com