[buug] backup devices

[f.johan.beisser]

On Fri, 16 Aug 2002, Skip Evans wrote:

> Hey All,
>
> What would some of you recommend for a backup device and software on a
> BSD box? Burnable CDs? We will be running a lot of list serves and need
> to archive all the email for legal reasons.

get a better email client. or, please start doing better wrapping. 70 char
a line or so will do nicely.

anyhow, for backups:

depending on how much data you need to back up will pretty much determin
what kind of hardware you buy.

since you're new to it, might i suggest taking a look at "UNIX Backup and
Recovery" from o'reilly. it's been fairly invaluable of a reference for
me, since it covers just about everything i needed to learn, and some that
i just didn't know enough about.

figure out how much data you need to back up, plan ahead. plan around a
media that will be around in 10 years, and can handle the volumes you plan
on doing. plot how often you'll be doing full backups (all of the data),
partials, and the rest of the crap. then, figure out what will meet your
needs as far as media is concerned.

for example, i use a couple Sony AIT2 tape drives at work. these are for
nightly backups of the main file server, each tape holds roughly 50 gigs
uncompressed, and 100 gigs compressed, data. since i do most compression
in software, i can push roughly 80 gigs on to the tape, with some work and
jockeying. this is only backed up once a week, in total, with lighter
dumps done every night or so. the nightly backup tapes are recycled every
month or so, with the full (level 0) dumps happening on a weekly basis.

on another server, i have a 5 tape jukebox (DLT), doing some network
backups with AMANDA (http://www.amanda.org) which is handling a large
portion of our developers stuff. each tape can handle rougly 70 gigs of
data, uncompressed. again, i do some software compression before the
archive is recorded.

the trick with backups is that there's no "One Good Solution" for
anything. if you plan on scaling, you have to be ready to change and spend
the money on the hardware.

the other gotcha to look out for is that media is not cheap. tapes are
expensive, and have a limited life. cdroms seem cheap, but you have to be
sure you've got a good format, and will have a way to recover the data in
X amount of years (there are entire companies dedicated to data recovery
from "dead" media). included in this is shelf life, how long the backups
are going to be viable. tape lasts years, how long does a dormant cdrom,
dvd-rom, or equivelent last? if you use a dvd-ram drive, will the format
of the dvd be readable to another dvd-rom?

one of my major complaints with backup solutions is that tape costs MUCH
more per gig than disk. the capasity of the average HD at home is well
above the capasity of the normal "home backup" solution. for example, you
can get a drive for roughly $2/gig these days (70GB/$140 or so). to get a
tape drive, and tapes to handle that much data, will run you roughly
$2500 for the drive, and about $50 per tape - depending on the kind of
tape it is and the kind of drive.

backups are expensive. not doing them is more expensive.

-------/ f. johan beisser /--------------------------------------+
  http://caustic.org/~jan                      jan at caustic.org
    "John Ashcroft is really just the reanimated corpse
         of J. Edgar Hoover." -- Tim Triche