Tape Backups are NEVER Reliable - EVER

In article ,
Ron Reaugh wrote:
best of all is in a granite mine on a different continent....well no best is
in quantum entangled storage in another galaxyg.

Your quantum entangled storage in another galaxy is no safer that wherever
you have the nearside qubits stored. There is no magic bullet, not even if
you invoke Arthur C. Clarke magic.

--
I've seen things you people can't imagine. Chimneysweeps on fire over the roofs
of London. I've watched kite-strings glitter in the sun at Hyde Park Gate. All
these things will be lost in time, like chalk-paintings in the rain. `-_-'
Time for your nap. | Peter da Silva | Har du kramat din varg, idag? 'U`

"mschlack" wrote in message
om...

-snip

One thing to clarify: do you have both restore and archive needs?
Restore would be to rebuild after a disaster or after losing or
corrupting specific files. Archive would be for
long term retention -- rarely used data that's taking up space
otherwise but would need to be occasionally mounted at some future
point (like parts drawings for obsolete products). If you're truly
archiving, then tape probably is a must (or optical), since the
reliability of data that's never read on disk drives can't be assumed
for many years (those little old bits can flip on you). SDLT is a
solid choice, in any event.

Tapes are NOT for long term storage. Only some opticals have been legally
approved.

In article ,
Ron Reaugh wrote:
Tapes are NOT for long term storage. Only some opticals have been legally
approved.

That depends on your application and environment, legal requirements may not
be a factor. We had 3480/3490 tapes that stored data in our archive that
had very few read errors after 15 years of storage and use. Of course,
they were kept in the climate controlled computer room for their entire
life time. It is common to be able to read 1/2" reel-to-reel tapes that
are 40 years old without too many problems as long they were stored in
reasonable climate conditions.

Now, however, with the increasing recording density of recent tape
media formats, it may not be possible to get that kind of lifetime.
Oozing of data to newer tape (or other storage) technologies may be
necessary after 5-8 years. Personally, I'd prefer to trust linear
recording formats over helical scan formats any day.

NCAR has an archive that is approaching 2 PB (petabytes), all of
it on tape. I suspect there are organizations with much more data on
tape.
--

Craig Ruff NCAR
(303) 497-1211 P.O. Box 3000
Boulder, CO 80307

In comp.sys.ibm.pc.hardware.storage Craig Ruff wrote:
In article ,
Ron Reaugh wrote:
Tapes are NOT for long term storage. Only some opticals have been legally
approved.

That depends on your application and environment, legal requirements may not
be a factor. We had 3480/3490 tapes that stored data in our archive that
had very few read errors after 15 years of storage and use. Of course,
they were kept in the climate controlled computer room for their entire
life time. It is common to be able to read 1/2" reel-to-reel tapes that
are 40 years old without too many problems as long they were stored in
reasonable climate conditions.

Now, however, with the increasing recording density of recent tape
media formats, it may not be possible to get that kind of lifetime.
Oozing of data to newer tape (or other storage) technologies may be
necessary after 5-8 years. Personally, I'd prefer to trust linear
recording formats over helical scan formats any day.

NCAR has an archive that is approaching 2 PB (petabytes), all of
it on tape. I suspect there are organizations with much more data on
tape.
Yes, in the early 90's the large company I worked for converted all of
the hundreds or thousands of history tapes from reel to 3480
cartridge. IIRC all of the tapes, some 10 years old or more, were
readable.
We also performed a yearly disaster recovery test wherein we would go
to a recovery center for 3 days and restore our IBM mainframe system
from 3480's. We'd have our entire disaster library shipped across the
state by truck to the recovery site. We never had any problems reading
the backup tapes.

Jerry

Keep working there as long as you get the personal advancement you
need to stay happy.
Wait for them to have a problem that the current backup solution
cannot handle.
Make sure you have your own way to recover everything.
When disaster occurs quit...
Offer to come back as a consultant at 3X your current pay rate to
oslve their problem.

On Tue, 22 Jun 2004 20:33:16 GMT, "Ron Reaugh"
wrote:

Tapes are NOT for long term storage. Only some opticals have been legally
approved.


Legally approved by what organizations?

Here are the methods of archival storage for a couple of the US's
largest data gathers:
Library of Congress
National Oceanographic Data Center

Of course, the Census Bureau has learned their lesson the hard way.
Due to the high costs of migrating digital data over time they are now
moving back to microfilm:
http://www.fcw.com/fcw/articles/2001/0108/web-census-01-09-01.asp


---

Here is the solution used by the US Library of Congress:
http://www.dlib.org/dlib/may96/loc/05c-arms.html#preserve
"To address the estimated need for 50 terabytes of managed storage by
the year 2000, the Library will be installing a commercial
hierarchical storage management system over the coming months. Storage
management software will transfer files automatically between high-
performance disk drives and less expensive storage media from which
retrieval will take longer. Typically, the location is based on time
since last access, but more complex rules can be enforced. Since the
highest resolution images will be accessed only occasionally, they
will usually be resident on the slower medium. The allocation is
transparent to applications accessing the files; "stub" files left in
the logical file hierarchy point to the physical location of files
that have been relegated to another "layer" of storage. For its second
layer of storage, the Library has chosen high capacity magnetic tape
cartridges under robotic control.

The tape unit (IBM's 3494 Tape Library Dataserver) has been installed
and is already in use for regular backup and restore operations
(associated with any computer system). Generation (and periodic
regeneration) of archival copies of collections on tape cartridges is
also possible for preservation of the digital materials. The
hierarchical storage management software (ADSM from IBM) will be
installed on individual computers over the next few months, in
conjunction with system upgrades. "

--

Here is the method used by the US National Oceanographic Data Center

http://www.nodc.noaa.gov/General/NODC-About/archive_access.html

"NODC currently operates a number of Digital Linear Tape (DLT) and IBM
3590 tape media systems for backup and archive and for off-line
storage. NODC operates automated systems to perform regular virus
scans of data in storage both during ingest and periodically
thereafter, and also to generate cryptographic checksums of all
digital archive data so that its integrity can be verified at any
time. This allows for a high degree of confidence that any data
corruption due to media failure or accidental or intentional
destruction can be easily detected so data can be recovered from
off-line backup media. It also allows for data migration across future
generations of storage media and systems with a high degree of
confidence in the inherent data integrity.

NODC also operates a number of high-capacity RAID (Redundant Array of
Inexpensive Disks) disk storage systems to support data ingest,
working storage, online products and database search and retrieval
systems.

Tape jukebox systems are maintained at NODC to provide automated and
manual backup facilities supporting the NODC workstations and servers
as well as near-line mass storage jukeboxes (the backup copy results
in a third copy of the original data). These systems currently use DLT
technology and run under the control of Legato Networker backup
software. Tape media systems are maintained to support data retrieval
from legacy tape formats such as 9-track, and to copy data to IBM 3590
tape media for offsite, deep-storage archive. Other tape systems are
provided for backup and restoration of database and critical data and
information servers."

--

And the method for the

On Wed, 23 Jun 2004 19:11:33 -0700, Scott wrote:

Keep working there as long as you get the personal advancement you
need to stay happy.
Wait for them to have a problem that the current backup solution
cannot handle.
Make sure you have your own way to recover everything.
When disaster occurs quit...
Offer to come back as a consultant at 3X your current pay rate to
oslve their problem.


Hmm, that's good advice.

~F

"Scott" wrote in message
...
On Tue, 22 Jun 2004 20:33:16 GMT, "Ron Reaugh"
wrote:

Tapes are NOT for long term storage. Only some opticals have been
legally
approved.


Legally approved by what organizations?

Tax data etc....the last time I checked only some kinds of optical were
approved.

On Thu, 24 Jun 2004 20:45:39 GMT, "Ron Reaugh"
wrote:


"Scott" wrote in message
.. .
On Tue, 22 Jun 2004 20:33:16 GMT, "Ron Reaugh"
wrote:

Tapes are NOT for long term storage. Only some opticals have been
legally
approved.


Legally approved by what organizations?

Tax data etc....the last time I checked only some kinds of optical were
approved.

Correct. For Europe there are only two systems (both optical) that are
approved for tax data.

That means, that only those systems are allowed when that system is
the ONLY place where the data is stored.

If the data is ALSO still stored on harddisk, then a tape backup is
enough.

Suprisingly almost nobody seems to know about these regulations. There
are lots of financial organizations that use archive media which are
not legally approved. (like CDROM)

Marc

On Sat, 19 Jun 2004 21:14:47 GMT, "Ron Reaugh"
wrote:

[ Snip ]

In short, I need some type of recommendation, in writing, in some type of
white paper, from some type of credible sources, that SDLT tape backup
drives, at least for the purpose of long term archiving

Tapes have NEVER been considered a viable "long term archiving" medium.

Neither, though, has anything else, except for paper.

Tape is, and has been proven to be, better than most things, and
particularly better than disk whose failure modes tend to result in
massive data inaccessibility more often than those of tape.

However, this issue is not tape-vs-anything else, it's on-line and
on-site vs. off-line and off-site.

[ Snip ]

Reliability is always the sum of all such factors and any backup strategy
should look more towards the least common denominator...Murphy....an
automatic corrollary to Murphiy's law is that tapes are unrelaible. The
proof of that is the incredible cycle strategies that have developed over
the years for tape backups. That comes from the fact that too frequently
the tape isn't usable for any one of a number of reasons.

Substitute "backup medium" for tape and there would be something
useful in the above...

Malc.