Re: Recommended swap for 2.4.x.

[Rik van Riel]

On Mon, 29 Jan 2001 [e-mail] wrote:
> On Mon, Jan 29, 2001 at 02:57:44PM -0800, Alan Olsen wrote:
> > 
> > What is the recommended amount of swap with the 2.4.x kernels?
> 
> AFAIK, swap requirements for applications running under a 2.4
> kernel have not changed significantly from 2.2 kernels

It has. We now leave dirty pages swapcached, which means that
for certain workloads Linux 2.4 eats up much more swap space
than Linux 2.2.

On the other hand, if you almost never used swap under Linux
2.2, you probably won't be using it under 2.4 either.

> 2) Subtract the amount of RAM you have (believe it or not, the more RAM you 
>    have, the less swap you need.  Imagine that).

For Linux 2.4, it may be better to substract a bit less,
because of the issue above.

If you have a very swap-intensive workload, you may end
up with 90% of your memory being "duplicated" in swap, in
which case this rule doesn't work.

regards,

Rik
--
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