Memory Question

Anthony Atkielski atkielski.anthony at wanadoo.fr
Thu Jan 13 12:30:38 PST 2005


Colin J. Raven writes:

CJR> I always understood in FreeBSD that "Free Memory is wasted memory"

In any operating system, free memory is wasted memory.  But if you
suddenly need more memory and you don't have it, system performance will
slide right down into the abyss, no matter which OS you are using ...
and very often it's cost-effective to "waste" some extra memory to
handle peak loads. Memory's cheap, anyway.

CJR> I compared this to the 5.3-RELEASE box of a colleague.
CJR>
CJR> AMD Athlon (1800-something-or-other) also 1GB RAM
CJR>
CJR> Mem: 467M Active, 224M Inact, 201M Wired, 33M Cache, 111M Buf, 71M Free
CJR> Swap: 4096M Total, 1672K Used, 4094M Free
CJR>
CJR> Other than the fact that swap doesn't add up (or doesn't seem to) the
CJR> box of my colleague seems to have a more "sensible" (classic) amount of
CJR> free memory.

No, he doesn't have enough memory.  A good operating system (which of
course would include FreeBSD) can make the best of the memory it has
under load, by judicious use of the swap file(s), but even the best
swapping algorithms are no match for more RAM.

You can never have too much memory.

CJR> Is there something I can do in order to "optimize" - which in this
CJR> case paradoxically would seem to mean "reduce" the amount of free
CJR> memory?

General rules: Reducing memory is never an optimization.  Increasing
memory never reduces performance.

-- 
Anthony




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