Assuming you have a dedicated server explicitly for database functions -- how much memory should you reserve for the operating system?
I realize this will probably vary somewhat depending on the specific OS, the specific database software, and so forth. But, as memory is so important to database performance, I want the database to have the maximum reasonable level of memory, without starving the host OS.
- what's a good rule of thumb to start with?
- what counters or performance indicators should we look at to determine if we've gone too far and the host OS is being starved somehow by the database?