RHEL memory questions

Am just starting working with Oracle (11g R2) over RHEL(5) and I have some basic doubts that I would like to clarify (until now, I’ve been working with Oracle over Windows):

• As part of a daily DB report, I need to check the memory usage of the server and am getting these:

total used free shared buffers cached

Mem: 62 61 1 0 1 55

-/+ buffers/cache: 4 58

Swap: 31 0 31

Total: 94 61 33

As you can see, “free” memory is almost over (although there’s no swap) which makes me report that memory usage is at 98% (it sounds strange to me), is this a normal behavior?; I’ve checked the processes running and there’s no a pick process but many opened by the oracle connections to the DB; depending on the answer, the next questions would be if more memory is required or if there’s a way to limit the memory that Oracle uses (on Windows, there’s a single Oracle process –with all subprocesses inside- and is very easy to determine and restrict the memory used by the DB, here in Linux seems like I need to sum the memory used by all processes for oracle user and seems not easy to restrict to a limit, is this correct?).

Any advice, tip or trick for an Oracle DBA over Linux is well received.

Thanks

David Ramírez Reyes
Profesión: Padre de Familia

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