Managing Kernal resource

Hello All,

I think I am little bit lost in congiguration of SHMMAX parameter.

As per documantation on :

http://www.redhat.com/docs/manuals/database/RHDB-7.1.3-Manual/admin_user/kernel-resources.html

Name Description Reasonable Values
SHMMAX Maximum size of shared memory segment (bytes) 512 KB + 8192 * buffers + extra ... infinity

"The most important shared memory parameter is SHMMAX, the maximum size, in bytes, that a shared memory segment can have. If you get an error message from shmget along the lines of Invalid argument, it is possible that this limit has been exceeded. The size of the required shared memory segments varies both with the number of requested buffers (-B option) and the number of allowed connections (-N option), although the former is the dominant item. (You can therefore, as a temporary solution, lower these settings to get rid of the failures.) As a rough approximation you can estimate the required segment size as the number of buffers times the block size (8192 KB by default) plus ample overhead (at least half a megabyte). All error messages will contain the size of the failed allocation request. "

As far as I understood is 512 KB+8192*number of buffers times the block +0.5M.B

But I am not getting the count of number of buffres.
In postgres.conf file there is size of shared buffer.

shared_buffer=24 MB.

can anybody point me to number of buffers if i have understood correctly

Thanks In advance.

With Regards
Ashish...