"swap" partition leads to instability?

RW rwmaillists at googlemail.com
Thu May 30 15:06:08 UTC 2013

On Wed, 29 May 2013 19:52:02 +0000 (UTC)
jb wrote:

> RW <rwmaillists <at> googlemail.com> writes:
> > 

> > BTW you mean paging, or swap use, rather that swapping. Linux
> > supports only paging, so it can be taken as read that swapping
> > means paging, but FreeBSD supports both.
> Yes, there is some confusion about the diff, if any, between paging
> and swapping.
> Paging - copying or moving pages between physical memory (RAM) and
> secondary storage (e.g. hard disk), in both directions.
> Swapping - nowdays is synonymous with "paging".
>   But its history is as follows (per Wikipedia):

This is a bit Linux-centric.

> You say that FB supports both, Linux supports paging only.
> Well, Linux utilizes swap space as part of virtual memory.
> So, can you elaborate more on that - what is the essence of the diff,
> why should I avoid the term "swapping" when referring to Linux,
> assuming VMM systems on both ?

You page-out pages and swap-out processes. 

When FreeBSD is very short of memory it swaps-out entire processes to
concentrate the memory in the running processes. Linux goes directly
from paging to killing processes.

You can also set vm.swap_idle_enabled to allow idle processes to be
swapped during normal use. This may help if a server has a lot memory
tied up in processes that tend to be idle for long periods of time -
traditionally used on shell servers. These days you'd probably want to
be adding more memory.

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