linux- out of free [duplicate]

Possible Duplicate:
free memory in Linux

I'm trying to determine if my server needs more memory.

free -m
             total       used       free     shared    buffers     cached
Mem:          7993       7719        274          0        372       5866
-/+ buffers/cache:       1480       6513
Swap:        11617          0      11616

The cached is high and free is low (the server handles a lot of requests). Is this indicative that the server could benefit from additional memory since all free memory is being used as cache?

No, that's what Linux does: it takes up the bulk of free RAM and uses it as cache. If processes require more memory, cache will be released for those processes.

The relevant line is the "-/+ buffers/cache" one, which indicates that you have 6.5 essentially free. Also of note, you're not using any swap, so you've haven't hit a high memory usage situation.