reading dump tape with bad spots

[Richard Childers]

In article <1084 at wpg.UUCP> russ at wpg.UUCP (Russell Lawrence) writes:

>Does anyone know of any PD dump/dumpdir/restor programs persistent 
>enough to skip over bad spots on tape?  

No, but I know of a few ways to test for bad spots on tape, if it's something
you've got the time and energy to be interested in.

Caveat - testing for errors takes time, you almost have to do the dump twice
and compare results before you can be *really* sure. The following methods
represent a half-hearted approach to verification.

	1)	test the physical media	of the tape

			dd if=/dev/rmt8 of=/dev/null bs=10k

	2)	test the internal consistency of the dump image by reading
		the bookkeeping data on it ( errors appear on stderr() )

			restore -tf /dev/rmt8 > /dev/null

	3)	act according to the results of these tests by remaking the
		dump image if necessary. Two extra hours now can save the
		day later ...

... both of these methods working together are quite good, albeit expensive
in time. But if you've got no other overriding responsibilities or can use
your time very effectively, doing this in the background as part of the dump
routine is an excellent way to guarantee good dump images.

>Thanks.

You're welcome.

>Russell Lawrence, WP Group, New Orleans (504) 443-5000
>{uunet,killer}!wpg!russ

-- richard


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