Subject: Re: [linux-audio-user] Linux swapping / multiple swap drives
From: Malcolm Baldridge (linux-audio_AT_paypc.com)
Date: Thu May 27 2004 - 22:17:13 EEST
> I have to hard drives, both containing swap partitions. The first hard
> drive also contains the OS and ardour sessions. The second hard drive is
> 'extra space'. I would like to use both drives for recording (not at the
> same time), but I'm concerned about how Linux selects which swap drive
> to use.
Depending on your RAM, you may want to disable swap during your sessions.
Fortunately, it's trivial to do: swapoff -a
Turning it back on is equally trivial: swapon -a
No, you don't need to reboot. [M$ and Apple have people a bit brainwashed in
that regard.]
> Ideally, when recording to drive 1 the OS would use the swap partition
> on drive 2 and vice versa.
It won't work that way. Linux will try to "evenly" use all swap devices so
as to maximise potential swap-in/swap-out performance. It cannot possibly
know that you're "intending to write large files" onto one of the drives,
and thereby "avoid using it for awhile". Remember that YOU (and to a lesser
extent) the application are best placed to KNOW what's going where and when
things are going to happen.
I suggest you do one of the following:
1) Disable swap on the drive onto which you're spooling the session data.
You can easily select which swap to turn on/tuff with swapoff/swapon on the
command line. Type "man swapon"
2) Turn off swap altogether. If you have 300MB of RAM or more, you
shouldn't need it to run your system. Remember, any extraneous activity can
potentially cause xruns or additional latency. It's best to consider your
DAW like an appliance during your recording work: focus it to perform just
the audio recording tasks, and it won't disappoint you. If you try to make
it a singing+dancing paperclip, server, chat system, and BitTorrent
downloader, you may find you start to have some occasional "burps" and
spikes in latency.
The Dark Lord disables swap on his Torture Servers when they have heavy loads,
=MB=
-- A focus on Quality.
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