Re: swap size for 2gb 2 processors?

On Thu, 21 Dec 2006 09:58:22 -0700, ray wrote:

On Thu, 21 Dec 2006 04:58:21 -0900, Floyd L. Davidson wrote:

General Schvantzkoph <schvantzkoph@xxxxxxxxx> wrote:
On Thu, 21 Dec 2006 11:22:22 +0000, Ron Hardin wrote:

How big should I partition swap for 2gb ram 2 processors? Planning
out a partition magic run on a 120 gb disk, sharing with windows XP.


The rule of thumb is 2 * RAM size, in your case that would be 4G. This is

There is no such rule of thumb for Linux, and *never* has been.
Use Google and learn something about it before you post false
statements.


Do you know what a 'rule of thumb' is? In days past, there was indeed a
rule of thumb if not a hearty recommendation for swap = 2*physicalRAM.
This was in the day before 1gb was fairly common, but indeed, it was there.

I got that figure (2 * RAM) from the Redhat manuals, probably RH5.2, or
RH6. It might be dated but there isn't a lot of reason to change it
because the price of disk storage is so low, 4G of disk space costs a
little over $1. Given that RAM and disk prices both follow similar pricing
curves (although disks were on a much steeper curve for a while) that
price for a swap partition has remained reasonably constant. If you don't
like the 2X rule how about substituting the $1 rule. i.e. your swap
partition should cost $1.

The purpose of having swap space has changed over the years. When virtual
memory was first introduced in the 1960s a large mainframe measured it's
core size in Kbytes. Virtual memory provided a means of handling multiple
jobs which could be swapped in and out of memory. Even into the 1980s the
main memory size of a large system was only a few megabytes so the swap
space was heavily used. Today most new PCs have at least 2G of RAM and 8G
can be had for about $1K. In today's world you should never be swapping, if
you are then you should add more RAM. The swap space is just an insurance
policy, it gives the OS a place to put things in the event you decide to
run a really large process that eats the entire memory. The 2X rule means
that you can swap out everything and then some. The $1 rule looks at it
differently, you are setting aside a trivial percentage of your disk space
as insurance that you won't ever run out of virtual memory.
.

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