Re: Pre-allocation of shared memory ...

On Fri, 13 Jun 2003, Lamar Owen wrote:

> On Friday 13 June 2003 11:55, Josh Berkus wrote:
> > Regrettably, few of the GUI installers for Linux (SuSE or Red Hat, for
> > example), include adequate swap space in their "suggested" disk formatting.
> > Some versions of some distributions do not create a swap partition at all;
> > others allocate only 130mb to this partition regardless of actual RAM.
>
> Incidentally, Red Hat as of about 7.0 began insisting on swap space at least
> as large as twice RAM size. In my case on my 512MB RAM notebook, that meant
> it wanted 1GB swap. If you upgrade your RAM you could get into trouble. In
> that case, you create a swap file on one of your other partitions that the
> kernel can use.

I'm not sure I agree with this. To a large extent these days of cheap memory
swap space is there to give you time to notice the excessive use of it and
repair the system, since you'd normally be running everything in RAM.

Using the old measure of twice physical memory for swap is excessive on a
decent system imo. I certainly would not allocate 1GB of swap! Well, okay, I
might if I've got a 16GB machine with the potential for an excessive
but transitory workload, or say 4-8GB machine with a few very large memory
usage processes that can be started as part of the normal work load.

In short, imo these days swap is there to prevent valid processes dying for
lack of system memory and not to provide normal workspace for them.

Having said all that, I haven't read the start of this thread so I've probably
missed the reason for the complaint about lack of swap space, like a problem on
a small memory system.

--
Nigel J. Andrews