[NTLUG:Discuss] Question about tape drives

[Terry Hancock]

On Friday 14 March 2003 05:02 pm, David Ross wrote:
> I hear you guys/gals talk about tape drives,but why not back-up to cd-r?
> i'd like to hear some pros and cons
> and i thank you for your time

Actually I do use CD-Rs -- exclusively.

I find that wholesale backups aren't very useful -- more often than not, 
backups are used to recover individual files that you actually erased by 
accident than say, hard-drive crashes.  Doing that from tape is notoriously 
slow.  And, tapes are fragile -- there is no sinking feeling like looking at 
the crucial backup tape only to find that it is stretched, melted, or broken.

On a Linux/Unix system it is particularly easy to separate unique user files 
from system files, and the system files which are actually unique to your 
system are also well-concentrated.  I see little point in backing up hundreds 
of .so files when they're all neatly packaged on my Debian install disk 
anyway. I'm pretty sure that an install takes less time than recovering from 
tape backups.

Also, I've noticed that useless cruft tends to build up on my system (log 
files I never bothered to delete, packages I really don't need or which are 
redundant, etc).  And the frequency that I have to recover a system is not 
unlike the frequency at which they need to be upgraded anyway.  Note 
especially that a blindly executed backup will also back up any trojan horses 
or other unauthorized or unintended corruptions of your system!

So, while I don't make complete "backups" very often, I make a lot of 
"archives" disks.

What I typically archive is the contents of all users' home directories, 
various shared project areas (by topic), and the contents of /usr/local and 
/etc.  If I'm being conscientious, I will also use dpkg (Debian package 
utility) to dump a machine readable record of the package database (I don't 
remember how you do this, but "man dpkg" will tell). During a Debian install, 
this can be read and used to install the exact collection of Debian packages 
that were installed before.  Then you restore /usr/local and /etc and the 
users' files, and you're back up.

Keeping the disks organized by topic (rather than say, trying to fill them 
all to capacity), is extremely useful when you're looking for an old file. 
And, typically, I never want to reuse the media, because these archives 
should be kept permanently.

Remember that the real genius is not in remembering the useful, but in 
forgetting the useless!

Cheers,
Terry

--
Terry Hancock ( hancock at anansispaceworks.com )
Anansi Spaceworks  http://www.anansispaceworks.com