> I would be very tempted to set up an old(er) PC with as 
> many drives in it as
> you want for the total desired capacity, and set them up 
> as a raid array, to
> mitigate against failure. Then have the one large drive 
> shared for access
> across the LAN.

As I said, backup not part of this consideration.
What I tend to do is to fill a say 300 GB drive with photos 
while manually mirroring master files to another drive.
When that is full the backup gets taken offline and the 
working copy is not written to. If the online copy fails the 
backup may be available :-).

When working on photos I make variants and derivatives of 
the originals. Some are worth saving in their own right and 
some are losable. By maintiaing a manual backup system I 
have freedom to decide what goes onto the backup disk. For 
example I keep a copy of the masters on both. I derive a JPG 
85 level compression of these and use them for making CD etc 
for on screen viewing. The quality is far better than neeed 
for screen viewing but for printing I would generally use 
the master. Even the JPG-85 is far better than what most 
people expect. The difference is a factor of about 3;1 in 
storage over the out of camera files. I usually shoot in 
"Fine" mode out of standard, fine, extra fine. I go to Extra 
Fine for portraits and high detail shots BUT the difference 
is usually almost impossible to see. RAW offers advantages 
but a big jump in memory size. I usually carry 12+ GB of 
memory cards which is OK for Fine mode but not for RAW. I 
saw a 24 GB CF card advertised yesterday, at 333X write. A 
48GB is coming. Price wasn't mentioned :-).

> A side effect of doing things this way is you could set 
> up, at a later date,
> another raid array to appear as a second drive for extra 
> capacity, or to
> mirror that array as further failure mitigation, with this 
> being invisible
> to the users, apart from downtime while being set up.

Indeed.
NTFS can apparently meld multiple drives under the same 
drive letter - even non RAID-hardware connected independent 
drives apparently. I haven't tried this and don't know the 
details of how it works.



        Russell

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