[CentOS] Swap Considerations

[Jim Perrin]

On 2/26/07, John Summerfield <debian at herakles.homelinux.org> wrote:
> > Using swap by itself is generally a speed penalty. Using a file for it
> > can be done, but it's not really something I'd do.
>
> Why not?

Habit, and I have yet to hear a convincing argument for why it's worth
the (admittedly minimal) trouble to configure as opposed to a normal
swap partition.


> OTOH anything bad you can do with /tmp you can do better with /var/tmp,
> and making that noexec is not a realistic proposition.

Very true, but applications like apache/php use /tmp as their default
scratch/upload space. While mounting noexec won't stop determined
folks, it may be a step that deters the more common automaded bot
attacks. It's by no means a total solution, but it's a layer that can
be used, and a layered security model is the best way to go in my
opinion. I use this in conjunction with selinux and mod_security for
my webservers which so far has been an excellent combination.


> For a personal system, I go with one big partition (well, maybe plus a
> little one for /boot).

My home systems are the one I'm most concerned about /home on (as I
tend to wipe and rebuild frequently) but I usually don't partition out
much else than /home and /boot.

> For a small server, same deal. If you don't know what you're doing, you
> don't have any chance of getting it right for you.

That's why he has us to ask :-P

> With Xen, I'm now contemplating several small systems under Xen, with
> shared storage (via NFS maybe, NFS should be fairly quick over virtual
> wire) where sensible, extra virtual disk where they need more private
> space. This is about what the Big Boys do with their zSeries.

If you're going to go that route, finish it off and make yourself a
virtual cluster with the CS/GFS stuff and use that for your shared
storage.


-- 
During times of universal deceit, telling the truth becomes a revolutionary act.
George Orwell