Boot problem True64 5.0a

Hello Admin Wizards,

when I came back to office from the weekend, one of my machines was down.

Having restarted it, I had a look at the /var/adm/messages that says 
_really_ very often:

vmunix: swap space below 10 percent free
unable to obtain requested swap space
last message repeated for 1143 times

I guess this might have something to do with the downtime.
What are the options?
Do I have to resize (?) the swap partition (I use advfs)?
Would it be good to reassign processes... (and if so, how ;o) ? )

Would be grateful for a hint

regards
CW