RE: Backup devices

[Paul Bunn <paul ultrabac com>]

It is my opinion that *every* tape should be viewed as medium-term storage.
If you take a DAT tape that has been in heavy-rotation (ie used in more than
50 backups), wait a year or so, there is a reasonable chance that not all
files will restore, and a small chance that the tape will be unreadable.
However, if you clean the heads, write a backup tape to a new medium, then
the chances are good that you could restore from that tape in 2-3 years.  It
does depend on the media technology being used of course.  My own personal
experience would tend to rate the following technologies from most-reliable
to unreliable:

IBM 3480/3490 (inc STK 9840)
DLT (inc DEC TK derivatives)
Ecrix **
8mm
4mm
OnStream  **
MLR / QIC with ECC code
QIC

** Best guess due to limited "real world" experience due to relatively new
technology

If you have a need for 5+ year retrieval, then you're not really describing
a backup device, but an archival one.  For this type of application, you
should really be using some flavor of optical storage, either Phase-change
MO, CD-R, DVD-RAM, COLD etc.

Other factors that are extremely important when dealing with reliability
with tape storage, is that of the environment in which the tapes are stored.
You will get much better results if the tapes are stored in a carefully
controlled environment for both humidity and temperature.  Tapes should
never be subjected to sudden temperature changes if at all possible.

Regards,

Paul Bunn, UltraBac.Com, 425-644-6000
Microsoft MVP - WindowsNT
http://www.ultrabac.com


-----Original Message-----
From: Uncle George [mailto:gatgul@voicenet.com]
Sent: Tuesday, January 04, 2000 7:54 AM
To: axp-list@redhat.com
Subject: Re: Backup devices


Tell me, how long do the data on the tapes last ? 1 year, 5, 10, 25 years ?
|
are these drives just short term backup devices. ?
signed
    afraid to look at my 8" floppies !

Paul Bunn wrote:

> I concur with this.  The Ecrix is a very nice low-cost drive, with
excellent
> (...)
> sThey also have _unique_ technology that makes the drive very reliable and
> robust -- packet reassembly, overscan and variable speed tape transport.
As
> a demonstration of the reliability of the technology they made a backup on
> tape, then took the tape, placed it in hot coffee then froze the tape
solid
> in a block of ice, then let it thaw and dry ..... then restored from the
> tape.  Apparently, this torture-test was repeated by a cynical magazine
> reviewer.