PostgreSQL: shared_buffers

1) if you have more than 1GB RAM, you can user 25% of memory for shared_buffers...

2) if you get error like «MSD FATAL:  could not create shared memory segment: Invalid argument» when you try to change shared_buffers size in postgresql.conf

shared_buffers = 1024MB   // default was 24Mb

you should increase the size of kernel shared memory

sysctl -w kernel.shmmax=1610612736 // (1.5Gb)

and try to start postgresql.