[mythtv-users] Backup LVM group (kinda OT)

mythtv-users at fastdruid.co.uk mythtv-users at fastdruid.co.uk
Tue Nov 8 14:59:41 EST 2005


Steve wrote:
>
> On Monday 07 November 2005 20:55, James Oltman wrote:
> > I am getting my hands on a slightly used DDS4 external SCSI tape 
> > drive. I am also getting about 7 tapes. 
<snip>
> 
> just so you know, tape isn't a great backup medium, your 
> better off buying a 
> 300gig harddrive, copying everything over and then storing 
> the harddrive in a 
> safe place. Or even just burning everything to DVDR. 

Bollocks, hard drives have electrics to go wrong as _well_ as all the
other problems with keeping those little magnets aligned. ;-)

Trust me, I've been there, I copied 160Gb to a drive, verified it was all
there, wiped
the original data and then discovered the 160Gb drive had died.

OTOH I was going through the archived tapes at work[1] and out of curiosity
tried the oldest tape I could find that we still had a drive for[2], still
worked fine.
If you're worried about wearing it out again don't be, we use loads of
different tapes in
various tape cycles, some are years old and get used every day. There are
tape libraries where
there are *hundreds* of tapes and the data is constantly swapped between
tapes, Should be _NO_ problem
with one small PC backup/restore!

In the past I've accidently booted a tape right the way across the machine
room with no ill effects,
try that with a hard drive (or even drop it, touch it after walking across a
nylon carpet etc etc). ;-)
DVDR's are better but still fragile in comparison to tapes and are _small_
in capacity.

Plus if you've got the drive free tapes are _cheap_, 4ukp (7usd) for
20-40Gb, 300Gb disks are 75ukp (ish, 130usd).
so worst case[3] 80% of the cost and if you _do_ get a failure you lose 7%
of your storage not 100% 
(and chances are you'll lose _some_ files rather than everything if a tape
dies). Tapes are _designed_ for backup,
hard drives are designed for _temporary_ storage space.

As for software I'd just look through the available packages included with
your distro, SuSE for example include
a backup option from yast.

If all else fails:

cd /video/recordings #or where ever
find *.nuv -print | cpio -oc > /dev/st0

read back with:
cd /video/recordings
cpio -ic < /dev/st0
(or cpio -itc < /dev/st0 to just read it back)

David

PS Don't rely on getting anywhere near 40Gb, that's compressed and movie
files don't compress well, more like 24-26Gb I'd have thought.

[1] Chucking the ones over 7 years old (we have to keep them for 7 years)
[2] 1989 
[3] ie no compression.



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