Recommended SWAP space for large amounts of ram (8GB)

RW rwmaillists at
Wed Sep 14 19:38:58 UTC 2011

On Wed, 14 Sep 2011 14:55:53 +0100
Matthew Seaman wrote:

> On 14/09/2011 13:34, Jonathan Vomacka wrote:

> > Either from the FreeBSD docs, or based on personal experiences,
> > what is the recommended swap space for a 8GB system? Your opinions
> > are greatly appreciated
> The old rule of thumb of swap = 2 x RAM dates back to the days when
> 128MB RAM was a big deal.  Nowadays, you're likely to have that much
> in your phone, and systems with 128GB RAM are not unknown.
> In these days of plentiful RAM, the new rule of thumb is "if you're
> swapping, then you're doing it wrong."  

There is a caveat that on desktop grade motherboards, expanding beyond
8GB can slow the system down, as populating 4 slots can cause the
memory to run at a slower speed.

> My recommendation: for systems with 1GB RAM or more, and that don't
> make heavy use of memory filesystems and the like, then 2GB swap is
> ample, and you can probably get away with as little as 1GB at need.

If you have 8GB of ram and you can get away with 1GB of swap, then you
presumably could get away with none.

This question recently came up on "hackers", and someone posted top
output from a 12GB system showing a 23GB openoffice process and 21GB of
swap in use after opening a large spreadsheet file. I think there's a
reasonable case for providing enough swap to cope with abnormal memory

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