Re: pre-p-2.0.31-2: out of virtual memory

Kurt Huwig (kurt@huwig.de)
Tue, 22 Jul 1997 21:05:44 +0200 (CEST)

On Mon, 21 Jul 1997, Ian Main wrote:
> > I'm getting an 'Out of virtual memory' running on pre-patch-2.0.31-2,
> > P133, 128MB RAM, 128MB swap, BusLogic, 3c509, 3c905, several EIDE and
> > SCSI disks, running a news server.
> >
> > I share a *lot* of memory, and I'm thinking I might be exceeding some
> > kernel VM limit. Is my addressable memory (given above config) 256MB,
> > or greater than that? What else might this problem be?
> Yes, the amount of VM on a system is equal to real RAM + swap space. The
> general rule of thumb is to have twice as much swap as real ram, so a 256M
> swap partition would not be out of the question.

I thought this 'rule of thumb' is from times of 8MB machines. I
experienced that a machine that has swapped out all of its memory (32MB
RAM + 32MB swap) is quite unusable.

BUT (!) this was running XEmacs, Netscape + Java-Applications altogether,
i.e. really using the memory. Iff you have some calculating stuff that
mostly uses localized data, you can easily go with 128MB * 8 swap (maximum
swap-size is 128MB, but you can use up to 8 partitions).

You should consider how much virtual memory you need and size your
swapspace according to this.

My machine has 64MB RAM and no swapspace and it works fine, using DOSEMU,
xemacs and Netscape.

A server certainly can swap out a significant amount of its memory,
because it isn't accessed for a long time, but still this won't be twice
the physical RAM. If this happens, your server would be so slow, you
should think about buying more RAM.

Kurt

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