/etc/sysctl.conf
fs.file-max = 65535
kernel.shmall = 4235264
kernel.shmmax = 4294967296
kernel.shmmni = 8192
kernel.sem = 8192 4194304 8192 512
/etc/postgresql/8.2/main/postgresql.conf
max_connections = 4096
shared_buffers = 1GB
temp_buffers = 2GB
work_mem = 512MB
maintenance_work_mem = 4GB
effective_cache_size = 4GB