Re: Backup

["Gary Hennigan" <glhenni@sandia.gov>]

kmself@ix.netcom.com, answering someone else's question, writes:
[snip]
> I'll second the Surestore recommendation.  I've got a 2GB DAT which has
> been used a little less frequently <g>, but does a great job.  Note that
> if you plan on aquiring more than about 15 tapes, the cost point
> between DAT and Travan/QIC breaks down about even.  DAT is solid,
> dependable, proven technology, and the media are cheap and reusable.
> Just what you're looking for in a backup.  The downside is that
> capacity, relative to today's drive sizes, is somewhat limited.  I can
> get ~4GB compressed, which works for me, but you'll have to look at
> higher capacity tape drives for your 9-40GB disks out now.

I'll third the DAT recommendation. I've got an OLLLDDDD 4mm drive and
it's been going strong for at least 6 years, AND I purchased
refurbished! One caveat though, make sure if you go DAT you get a
couple of cleaning tapes. They're pretty sensitive to gunk on the
head.

> > Whether or not the software appends or not, is in part predicated on
> > where the tape is when the run gets going.  Device /dev/nst0 doesn't
> > rewind, while /dev/st0 does.  If the backup software always rewinds,
> > and doesn't search for an EOF marker before writing again (i.e. knows
> > to append) you'll be out of luck.
> > 
> > If you use commercial software, check the specs first.  If you write a
> > simple 'tar' script, you can do what you want.
> 
> On this.  Unless you have specific requirements to meet (eg:  management
> can't keep from fucking with a technical decision), I'd choose the
> simplest backup methods possible.  My own local backup script is:
[snip]
> Tar isn't the sexiest thing out there (honey is <g>), but damned if it
> doesn't work, and if the tools for accessing archives aren't available
> on every flavor of Unix, and most lesser operating systems, not to
> mention boot, rescue, and minimal installations of Linux.  You
> *will* be

I think this is less true today than it has been in the past. If you
have a CDR or some other high-capacity recordable media it doesn't
take much to just build yourself, for example, a rescue CD. Or with HD
prices so low just having a second disk as a rescue device is probably
not unreasonable.

Personally I have my entire Linux setup copied on a CDR and so I have
anything I could possibly need in order to do a restore right
there. Plus, most of the software included in Debian is GNU and thus
most of it could be compiled on another Unix platform if you had a
need to read the tapes on a system other than the one on which it was
created.

Tar does have some problems. If your tape becomes corrupted somewhere
along the line you've pretty much lost that whole backup. Tar has
little to no capability to recover from tape errors, and if you use
some type of software compression with tar, like gzip or bzip2, you
might as well throw that tape out if it gets an error.

Also, if you have a lot of data I'd recommend something that allows
you to do incremental backups. All my data barely fits on two 2GB DAT
tapes with software compression, but with incrementals that's not an
issue. I can fit 3 or 4 months of incrementals on a single tape no
problem.

> Other general recommendations -- dump, cpio, and apio.  I'd generally
> *avoid* using an integrated backup management solution -- far less
> portable, and you may *not* be able to get at your data, unless you are
> part of a large and well-supported organization.  You get some plusses
> -- usually a searchable index or other log of what was archived, but it
> costs you in terms of flexibility.

I used to use dump in my sysadmin days and really liked it. The
drawback of the Linux version, at least the last time I tried it, is
that it won't back up any non-Linux partitions, e.g., Win98/WinNT. And
I think you meant "afio" rather than "apio"?

Just to give another point of view, I use an integrated backup
solution, afbackup. I do an incremental about once a week and other
than a manual full backup about 4 times a year, and a VERY rare tape
change, I never have to touch my backup software.

Lot's of choices for the original poster and about as many
opinions. Good luck!

Gary Hennigan