I'm trying to set up a DB server so it has plenty of RAM (for Postgresql 8.2). The Postgres instructions suggest modifying the values for these kernel variables:
OK. No problem, I can do that (I know where to set them dynamically and at boot time).
The examples and explanation are as follows:
For example, to allow 128 MB, and explicitly set the maximum total shared memory size to 2097152 pages (the default):
$ sysctl -w kernel.shmmax=134217728
$ sysctl -w kernel.shmall=2097152
OK. I get SHMMAX (maximum total shared memory--I actually want more like 384MB).
Someone please tell me what kernel.shmall=2097152 pages means. What does page mean in this context and how does this relate to SHMMAX?
(Frankly, I don't want to set this value to the default, I want it to be big--the server has lots of RAM and I want to use it.)
Thanks for any insight you can give me.