[ On Monday, May 26, 2003 at 08:37:27 (+0900), Curt Sampson wrote: ]
> Subject: Re: Remote Backup Options (Was: Ripping and Storing CDs)
>
> Actually, at least for my purposes, this kind of thing doesn't really
> make a difference. I'm doing backup (for disaster recovery), not
> archiving, so losing the backup is merely an annoyance so long as the
> original is intact. I just have to make another backup.

Ah!  That's a very good point!  I was trying to figure out how to say
much the same thing.

> For archiving, of course, the situation is quite different. For that,
> I'd suggest you make a copy of your important tapes, and test both the
> originals and the copies on a regular basis. When either has an error
> rate that is too high on a test read, make another copy before further
> degredation occurs.

Given the rate at which storage capacity per unit of cost keeps
increasing I'm considering that I don't realy need archives any more.
If I've had to look at any of my old tapes any time recently I've simply
loaded the whole thing onto my file server and left it there.  For true
disaster recovery I need the same amount, or more, of capacity off-site,
so I've not had any reason to generate new archives of anything in quite
some time -- I just keep it all on-line all the time now.


However I'd still put my bets on the data on disk drives properly stored
in a safe deposit box rather than on any modern high-capacity tape media
such as SDLT.  If you're going to allow re-spooling, cleaning, splicing,
and such of tapes taken from a damaged safe then you've got to allow the
same kind of thing for disks too.

I can have all the data recovered from even a very badly damaged disk
for only a few hundred dollars.  If an SDLT tape gets soaked with hot,
soot-contaminated water, I'll bet there's going to be a lot of bad bits
on it even if it is cleaned and re-spooled very carefully (those bits
are awfully close together!).  I don't know how much that procedure
might cost, but it won't be free.

Meanwhile so long as the heads stay locked in my big ATA drive (which
for a 160GB drives costs only about $0.30/GB more, and 45% larger, than
the (un-compressed) SDLT media alone), and the integrity of its HDA
doesn't get compromised by shrapnel (quite a bit less likely to happen
than the DLT cartridge I'd think, even in an event like the bank vault
break-in shown on CSI recently), I may need no more than a new motor and
electronics to spin up my hard drive again, and even if its spindles
have to be moved to a new HDA, that's still not too much more expensive.
Meanwhile I don't have to buy an $8k-15k SDLT drive!

-- 
								Greg A. Woods

+1 416 218-0098;            <g.a.woods@ieee.org>;           <woods@robohack.ca>
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