[NTLUG:Discuss] Amount of Swap

[Christopher Browne]

On Sat, 26 Aug 2000 08:02:04 CDT, the world broke into rejoicing as
Bug Hunter <bughuntr at one.ctelcom.net>  said:
> On Thu, 24 Aug 2000, David Neeley wrote:
> 
> > I've been told that Linux swap should be approximately double the RAM size,
> > but more than 128 MB is unnecessary. Is this your experience?
> 
>   Actually, until recently, only 128MB of a swap file would be used.  I
> think this limit is lifted now, but i'm not sure.

It's been a couple years since the 128MB limit was raised; I think that
was something added in 1.3.  Or possibly 1.2...   Pretty ancient history.

At any rate, the "double the RAM" thing was a _required_ metric for
systems based on BSD, until probably five years ago, as part of the
fundamental design of virtual memory.

It is _not_ a forcible requirement for Linux, and, with ever-increasing
physical RAM on machines, it is becoming less and less true as even a
"rule of thumb."

It is probably a good idea to have _some_ swap; that means that if you
overextend physical RAM, processes don't just _die_.

But if you have 128MB of RAM, and never make use of more than 32MB of
swap, then it would be quite reasonable to have somewhere around 32MB
of swap.  Vary the numbers as necessary...  But it is probably unusual
to have a system work well when more than 100MB of swap is in use...
--
cbbrowne at ntlug.org - <http://www.hex.net/~cbbrowne/>
"sic transit discus mundi"
-- From the System Administrator's Guide, by Lars Wirzenius