Notes on Increasing Swap Space

General Idea:

You can increase the FreeBSD swap space either by repartitioning your disk and reinstalling FreeBSD, installing a new disk, or creating a virtual swap space in a file in the normal file system. The latter of these is the least painless and noted here.

For the best info, look in the FreeBSD FAQ. This was the appropriate link when this page was written. Search for "Swap Add" in the FAQ at the FreeBSD site if things seem out of date.

Local notes:

Here's an e-mail message Mark Parris sent out when we started making the change here:
FreeBSD folks,

I changed the CS config file in /usr/src/sys/i386/conf to have the

pseudo-device   vn      1

This is the line that allows us to use a pseudo swap space that is
actually a file.  Those of you doing kernel compiles will want to add
it to your config files as well in order to use the virtual swap

Also, rc.conf has:

swapfile="/usr/swap0" instead of "NO"

now so you'll need that in your various rc.conf's if you want to take
advantage of the swap file. 

Floyd now has an additional 32MB of space, bringing it up to 72MB.
Other machines will probably see increases shortly as well.

Information on adding swap space in this way can be found at:


Other DiRT documents
Author: Mark Parris
Last updated: December 3, 1997