On Tue, 13 Jun 2006 at 4:04pm, Paul Bijnens wrote
http://wiki.zmanda.com/index.php/Restoring_files#Using_amrestore_with_split_dumps
In that explanation I used amrestore to fetch the chunks from disk to
tape, but doing it with a shell script is still doable:
- read the first 32K block of the tape chunk
- get the first line and decide if this is the a chunk you need
(we can still keep the requirement that chunks should have been
written monotonously, but they can be interspersed with other chunks)
- if not, just skip to the next tape chunk
- if yes, save the rest of the tape chunk to disk
- output that chunk to stdout when reading the next chunk header and
that has a different number (because incomplete blocks are rewritten
in the beginning of the next tape).
So it sounds like tape chunks are just like full dump images, with the
standard 32KB amanda header with added info about which chunk it is.
That's a Good Thing. Thanks for the pointer when I was being lazy.
Given that, interspersing chunks from different images could be done
without creating too much extra hassle. *But* I don't know that I see the
utility. You liked the idea of starting to tape a dump from holding disk
before the dump from the client is done. While I can see the utility,
what happens when the client or the network dies mid-dump? You just
wasted a bunch of tape.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
