WARNING - Sorry, no answers, but rants about backups and media follow.
After having paid my stupid tax multiple times, please remember what I
did not (at least not often enough) the 3-2-1's of backups.
3 copies, 2 DIFFERENT media, 1 offsite.
These are minimums to have mostly retrievable backups.
I have used this with an automated system, where there was one copy
kept on a local 'backup disk' drive, the second copy was on tape in a
tape library, and the third was written to tape and it was sent
offsite. If there was space keeping two copies offsite helped make
disaster recovery testing more successful. This particular backup
software kept a database (and a copy of it went to tape and offsite
daily too) where it know where each version of each file was on all
tapes and disk (onsite and offsite) at all times. This may be
overkill but it allowed the same system to be used for disaster
recovery AND for daily 'awe shucks' backups (to recover a file or
directory randomly due to problems, mistakes, or malicious events).
I used several kinds of tapes over the years, and even with that level
of redundancy, being able to retrieve data still fails at times. But
this is the best rule of thumb I can determine.
The idea is if you make 2 tapes (say DAT or LTO or DLT) you still need
to keep a copy of the backups on disk or dvd or whatever.
If selecting tapes, my current preference is LTO as DAT and 8mm are
both subject to significant reliability issues and DLT is getting hard
to find replacements for. There could be other media out there, but
just throwing disk at it seems to be in vogue but for archival and
long term backup, I don't think so.
There are 'tape replacements' that make disk files emulate tapes, but
those never seemed to catch on. (my gut feel told me this is the
worst of both worlds).
An old co-worker, Curtis Preston, has a blog on his site
backupcentral.com . ... Curtis wrote the O'Riley book on Unix Backups
initially while we both worked for a consulting firm. Even with that
lapse of judgement for both of us, he is still a great storage /
backup geek.
http://www.backupcentral.com/mr-backup-blog-mainmenu-47/13-mr-backup-blog/412-get-rid-of-tape-inconceivable.html
In the blog post above, they talked about the current state of tapes.
Evidently LTO5s, store 1.5T on a tape uncompressed, and seem to be the
current state of the art in tapes.
In yet another aside, I suggest registering with backupcentral.com and
tell Curtis I sent you. Then go to his wiki pages and look over the
'popular posts' section. A wealth of information for you to digest in
your 'spare time'.
(Curtis is a high $$ storage and backup consultant these days. I
doubt you want to hire him, but he is also helpful if you need some
hints in the mean time.)
My experience with LTO tapes (back in gen 1 & 2) were that
manufacturers do matter. Both in drives and media. HP, and IBM did
quality control on the tapes with their brands and were a cut above
others. That designation may have changed. There are several big
names that did a consortium to engineer LTO drives and media to get
reliability up. The prices of tapes have also come WAY down over the
years.
If anyone is interested I have stashed away some good information on
using CD and DVD media for archival storage. The basics are,
manufacturers matter, proper storage matters, and you should get about
50 years (real world, not theoretical) from 'good archives', the trick
is no one will have the hardware to process it by then. ( I know where
I can get a 80 column Hollerith card reader or an 8 level paper tape
reader now days, but finding a 256BPI magnetic tape drive that works
would be problematic! ) Several 'pros' I have spoken with suggest
that you read all media every 6 months, and write it to NEW media
every 5 years whether it needs it or not if you really want to keep
digital archives. I have no clue what the Smithsonian current policy
is, but it would be interesting to find out.
><> ... Jack
Whatever you do, work at it with all your heart... Colossians 3:23
"If you are not part of the solution, you are part of the precipitate"
- Henry J. Tillman
"Anyone who has never made a mistake, has never tried anything new." -
Albert Einstein
"You don't manage people; you manage things. You lead people." -
Admiral Grace Hopper, USN
Life is complex: it has a real part and an imaginary part. - Martin Terma
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