[9fans] using plan9 fs for archive from other OS?

[a@9srv.net]

at work we run a handful of Win32 servers (god help me) and a
few unix servers. we're doing tape backup nightly. our full
backups are at the limit of what our tape drive can deal with
and are still growing. so we need to come up with a different
solution.

and, more to the point, i *HATE* tape backup.

further, plan9's dump fs is the best backup system i've ever
seen (and, along with /lib/ndb, the thing that made me fall
in love with the system as a sysadmin).

so... any suggestions on how to use either the old 3e fs,
fossil, and/or venti to perform backups from non-plan9
systems? the largest system generates about 50-60GB for a
full backup (of the data we care about backin up, which
isn't most of the system), thre's two more in about the
20-30GB range, and we don't currently have numbers for how
much changes incrementally (but i believe it to be about
10% daily). Almost all of the data lives on Win32 servers.
Preserving metadata (specifically, dates, ownerships, and
permissions) is important.

tips? comments? experiences?

much thanks,
ア