TMG-L Archives

Archiver > TMG > 2002-01 > 1010061283


From: "Jerrod Carter" <>
Subject: RE: [TMG] A Cautionary Tale - Backups
Date: Thu, 3 Jan 2002 07:34:43 -0500
In-Reply-To: <014d01c193fa$6760f8c0$1c55d840@g2u2m0>


Gale Gorman wrote:

>I am moving from years on a UNIX system where complete backups are
>normal and standard. We always rotated a series of tapes with one
>offsite at all times. These tapes get reused as long as no error
>messages are reported by the 'verify pass' and I have used some over
>and over for years.
>
>The point is they are ALWAYS overwritten with the latest stuff. Why
>would you want to append them?

For a permanent versioning system. When you rotated tapes, there was only a
certain amount of time you could go back. Perhaps thirty days. If a user of
the UNIX system discovered that their file had been accidentally deleted
more than thirty days prior to the discovery, then your tape rotation scheme
would not allow them to recover that file. Similarly, if their data became
corrupted thirty days prior to the discovery, it would not be recoverable.
If you increase the rotation scheme to a sixty day cycle, it's better, but
still not foolproof.

In genealogy, we don't look at some people for very long periods of time.
With some folks have 50k+ people in their database, some folks might not get
looked at for a very long time indeed. If something happens to corrupt a
person's data, and it isn't discovered for a long time, it might take a very
old backup to put things right again.

Jerrod Carter

This thread: