Need some email/colo service -- recommedations?

Robert L Krawitz rlk at alum.mit.edu
Tue Mar 2 10:49:03 EST 2004


   From: Chris Devers <cdevers at pobox.com>
   Date: Tue, 2 Mar 2004 08:56:16 -0600 (CST)

   On Tue, 2 Mar 2004, Johannes B. Ullrich wrote:

   > IMHO, tapes are just too expensive. Overall, I am switched almost
   > exclusively to backups to disk/CD/DVD. Tapes may be an alternative if
   > you already put the money down for a big auto-loader. But hard disks,
   > which now drop below $1/GByte, are very attractive.

   Yeah, but hard drives are fragile things, and optical media
   (cd/dvd) tend to be read-only (a minor point, I know -- yes I've
   heard of cd-rw). Newer media formats may have fallen below tape in
   cost, but are they proven to be as reliable as plain old-fashioned
   tapes yet?

Surely the read-only aspect of CD's and DVD's is attractive?  With CD
blanks now in the $.10/GB and DVD blanks in the $.30/GB range that
looks good, particularly if you have a decent incremental backup
scheme.  I never understand why people like to recycle 8 mm and 4 mm
tapes; they're awfully fragile and not particularly cheap anyway.
You'd need to get something like 10 cycles or more to beat CD's on
price, and I certainly wouldn't trust a tape I've already recorded on
10 times.

Old-style 9-tracks and 3490's (or whatever those things were -- they
came in a cartridge and were linear feed) are a different matter, but
that's certainly not cheap.

   Hard drives always seem to fail within a few years, and there have
   been suggestions that CD-{R,RW} won't be reliable beyond five or
   ten years.  Tapes are fragile too, but if cared for reasonably well
   it seems like they can work for decades. Will that be true for hard
   drives & CDs?

As I recall, NASA recently had trouble extracting data from 30 year
old 9-track tapes.  Not because the data got lost but because they
didn't have software any more that could read them.

   I'm curious how far you've thought this through. The appeal of
   backing up to big, cheap hard drives is obvious, but do you really
   trust those drives to be around when you need them? They seem too
   fragile to me...

Maybe back up to both BCHD's and two sets of high quality CD-R's, and
keep them in different locations?



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