This was reproduced on 7.4. I don't know if it is still an issue on 8.0. If you set shared_buffers (shmem_max) to greater than the shmem config on the OS pg will not start. And gives a useful message (below).
However, if you use the -B option on the pg_ctl start up, postgres starts up fine. And the shared_buffers value shown by show is the higher value. These options should work the same. --elein [EMAIL PROTECTED] waiting for postmaster to start...2005-01-04 01:20:09 [45468] FATAL:could not create shared memory segment: Invalid argument DETAIL: Failed system call was shmget(key=2010001, size=555876352, 03600). HINT: This error usually means that PostgreSQL's request for a shared memory segment exceeded your kernel's SHMMAX parameter. You can either reduce the request size or reconfigure the kernel with larger SHMMAX. To reduce the request size (currently 555876352 bytes), reduce PostgreSQL's shared_buffers parameter (currently 65535) and/or its max_connections parameter (currently 138). If the request size is already small, it's possible that it is less than your kernel's SHMMIN parameter, in which case raising the request size or reconfiguring SHMMIN is called for. The PostgreSQL documentation contains more information about shared memory configuration. .............................................................failed pg_ctl: postmaster does not start ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly