What are you trying to do:
         1) Swap on an NFS mounted file.
         2) Create a file on an NFS exported partition that you
            can swap to?

For #1 you modify /etc/fstab with a line like this:
     server:/export/swap   nfs      swap sw,nfsmntpt=/swap,priority=0 0 0
The important bit is that you make a directory /swap and you make
sure that the file is exported from your server and the server's IP address
can be resolved (put it in /etc/hosts of root for example.)

For #2 the easiest way is to use dd to copy some number of blocks from 
/dev/null
into a file that you're going to export with NFS. On any UNIX and probably 
Linux
you can type:
         dd if=/dev/null of=swapfile bs=1024 count=16384
bs is block size and I set it to 1K because it means I can create 'n' megabytes
by multiplying n by 1024 and using that as a count (so in this case its 16 MB)

--Chuck

At 11:35 PM 9/29/99 +0200, Wolfgang Rupp wrote:
>Hello!
>
>I have set up my VS3100M38 to netboot from a Linux box. Since I am
>a newbie to NetBSD and VAXen, I sticked exactly to the "VAX Netbooting
>HOWTO", and everythig worked fine. Unfortunately, I destroyed the
>swapfile and I am absolutely unable to recreate it correctly.
>
>What happened, actually, is that I that the SCSI controller in the
>PeeCee decided to bus-error, and the disks were in a less then optimal
>state after that. (Since this is a civilized list, I will not repeat my
>comments ;-)
>
>Could you please tell me or point me to a doc?
>What "apropos swap" brings up did not get me a clue how to create
>a swapfile in NetBSD. Swapping is done over NFS to the Linux box.
>
>Thanks.
>
>Wolfgang