max_connections =  200 
superuser_reserved_connections =  2 
shared_buffers =  20000  
max_fsm_relations =  100 
max_fsm_pages =  30000 
max_locks_per_transaction =  256  
wal_buffers =  32          

[root@dbserver]# su - postgres -c "ulimit -a" -s /bin/sh
core file size        (blocks, -c)  0 
data seg size         (kbytes, -d) unlimited
file size             (blocks, -f) unlimited
max locked memory     (kbytes, -l) unlimited
max memory size       (kbytes, -m) unlimited
open files                    (-n)  16384 
pipe size          ( 512  bytes, -p)  8 
stack size            (kbytes, -s)  131072 
cpu time             (seconds, -t) unlimited
max user processes            (-u)  384 
virtual memory        (kbytes, -v) unlimited

[root@dbserver]# ipcs -l
....
------ Semaphore Limits --------
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 32
semaphore max value = 32767
...