max_fsm_pages, shared_buffers and checkpoint_segments

["Y Sidhu" <ysidhu(at)gmail(dot)com>]

I am a newbie, as you all know, but I am still embarassed asking this
question. I started my tuning career by changing shared_buffers. Soon I
discovered that I was hitting up against the available RAM on the
system. So, I brought the number down. Then I discovered max_fsm_pages.
I could take that up quite high and found out that it is a 'disk'
thing. Then I started increasing checkpoint_segments,which is also a
disk thing. However, setting it to 25, and then increasing any of the
other 2 variables, the postgresql daemon stops working. meaning it does
not start upon reboot. When I bring shared_buffers or max_fsm_pages
back down, the daemon starts and all is normal. This happens on a 1 GB
RAM machine and a 4 GB RAM machine. 

Anyone know what I am doing wrong?

System:  FreeBSD 6.1, Postgresql 8.09, 2 GB RAM

-- 
Yudhvir Singh Sidhu
408 375 3134 cell