[9fans] fossil+venti vs. cwfs - dealing with backups

[Lyndon Nerenberg]

What has kept me running fossil+venti is the ease of backing up the file 
server.  Copying the venti arenas offsite is trivial.  And Geoff put 
together glue to write sealed arenas to blu-ray as well.
I don't see any simple way to do that with cwfs*.  Or hjfs.  I am very 
curious to know how the not-fossil/venti FS servers are backing up. 
Share?
--lyndon