New Opteron box, dedicated to PostgreSQL

[Claus Guttesen]

> while configuring my 1st PostgreSQL box with dual Opterons (2212) on
> FreeBSD, I have some questions:
>
> 3. What are the recommendations for tuning I/O)?
>     - setting sysctl vfs.read_max to 16 or 32
>     - rebuilding the relevant filesystem with 32K blocks and 4K frags
>     Are these reliable?

The following were suggetions from Vivek Khera:


/boot/loader.conf:

kern.ipc.semmni=256
kern.ipc.semmns=2048


/etc/sysctl.conf:

kern.ipc.somaxconn=2048
kern.maxfiles=65536

# Suggestions by Vivek Khera from postgresql performance
kern.ipc.shm_use_phys=1
kern.ipc.shmmax=1073741824
kern.ipc.shmall=262144
kern.ipc.semmsl=512
kern.ipc.semmap=256


This is on a four-way woodcrest at 3 GHz and 16 GB ram so you may want
to adjust the values.

regards
Claus