off site backups are a possibility, but that's going to depend on your line speed.
let's say that you have a 20Mbps SDSL line
you'll be able to transfer 2MB per second, you've got 409600MB to transfer.
that'll take 204800 seconds.
that's 56 hours...
basically, off site backup is probably not going to be an option, if you don't mind starting Friday night, maxing out your business upload bandwidth and your bosses download bandwidth, (assuming that they have 20Mbps ADSL) for all Friday night, all weekend and into Monday morning...
yeah, and that's assuming that you have 20Mb of upload bandwidth too...
and it ignores the fact that you'll never get those upload or download speeds because you're line will likely be contended, and even if your business line isn't contended, your bosses home line probably will be.
you could go for a tape backup solution, but you'll still have to change the tapes.
wireless, (assuming wireless G) 54Mbps.
that's 5.4MB per second and it still takes 21 hours... perhaps a Friday night/weekend backup might not be so bad.
wireless N (assume the fastest speed available is 150Mbps it'll take 7.5 hours
so your only viable wireless backup solution is using wireless N at the fastest speeds currently available.
that unfortunately ignores three things.
I've never seen a NAS device fitted with wireless N
I imagine that if such a thing did exist it'd be prohibitively expensive
you won't get decent reception from inside a fireproof safe. (so you'll get much lower than Ideal speeds).
cables going into your fireproof safe are going to make the safe no longer fireproof. -so you defeat the whole object anyway...
best bet for backups is, buying a leased line (as in a 100MB leased line that only you are using), and employing an outside company to do the backups for you, (as in you get a leased line to a data centre that terminates at their equipment).
you do on site backups to disks or tapes and swap them as you are doing.
or you rationalise the stuff that you want backing up so that you can backup over the internet to your bosses house.
to complete in 9 hours on a 20Mbps line you'll need to reduce the amount of data you're backing up to about 64GB. (and again that assumes maximum speed from 9 pm - 6pm with very good upload speed, good download speed both working at 20Mpbs all the time with no latency...
basically, the best way to backup is what you;re already doing.
it is a pain to swap out tapes of disks each day, but it's a pain that you have to put up with because it's an even bigger pain to loose all the data...
there is a final way to do it.
buy rack space in a data centre host all your data there, do your backups there, then have the data centre staff change the tapes/disks for you!
