From owner-freebsd-questions  Thu May 25 10:46:12 2000
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To: brendan@bmk.com.au
Cc: questions@freebsd.org
Subject: Re: How do I set up a swap file ?
Date: Thu, 25 May 2000 13:46:06 -0400
From: Brian McGovern <bmcgover@cisco.com>
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>
> I want to set up a swap file ( ie. a file on an existing ufs ) to be
> used as additional swap space.
> 

The easiest (and only) way I can think of doing it is to use the vn device,
so you'd do something like:

dd if=/dev/zero of=/<blah>/swapfile bs=1024 count=262144
vnconfig /dev/vn0 /<blah>/swapfile
swapon /dev/vn0c

In short, the first line creates a swap file. In this case, it should be
~256MB, unless I did my path wrong (possible).

The second like uses the vn driver to map your file to the /dev/vn* devices.

The third line tells swapon to add this "device" as swap space.

Overall, it'll work, as I've used this method before. However, there will be
quite a performance hit over a native swap partition.

	-Brian


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