[Info-vax] ODS-5 data/file recovery

[gce at gce.com]

On Friday, February 15, 2013 10:04:28 AM UTC-5, MG wrote:
> Recently, during a strangely botched file transfer via CIFS, a file was
> 
> somehow removed in the process (and wasn't successfully transferred
> 
> either, with nothing left as a result) and I don't seem to be able to
> 
> restore it through the usual methods (e.g. "DFU UNDELETE").
> 
> 
> 
> I've also tried to see what I could do, via "ANALYZE /DISK" and (later
> 
> also "/RMS", although the latter was rather pointless, as it's a Zip
> 
> file).
> 
> 
> 
> Are there any alternatives for data/file recovery?  Besides expensive
> 
> data recovery services.  It's an ODS-5 volume.  I'm for now making an
> 
> image back-up for the disk, I also noticed that I could see string of
> 
> the file (or filename, rather) that became 'lost' (whilst mounted
> 
> 'foreign') and that may be a good starting point.
> 
> 
> 
> Any tips, advice, pointers and help are most welcome.
> 
> 
> 
>   - MG

Your best bet, for a single file, is just to dump the index file to look for some of the filename (or dump a directory and see if file ID may still be there), then follow retrieval pointers by hand (or by tool if a tool works) and
copy the data off. You'll want some tool that grabs LBNs and dumps (or if doing this under linux, use dd).
It is probably worth while to look at the end blocks first if this is a zip file. If they are clobbered it can be very hard to get anything.

When ods-5 came in, much was made of the point that an ods-2 volume could be converted in place, without moving everything around. The change was made to allow long filenames with case information, and was not intended as a massive roto-till of the structure. Most of it (and importantly the retrieval pointer business) would work the same.
  Losing files due to accidental deletion is common everywhere. If you want to have precautions to avoid this, note safety has such (available over at www.gce.com) but it has not been built for awhile and might need tweaking to get it working again. Also it predates IA64 so a few dragon's teeth are to be expected if you want to get it going on one of those boxes. It does work on vaz or alpha. The scheme of catching files before they go is however useless in situations like this. Good thing there is SOME backup in existence.
Glenn Everhart