Re: Stand-alone slices

Denis,

Thanks for the reply.  First let me restate what I have learned from your reply.

In the development version:
- The slicing scheme is recoverable from any slice as it is encoded in all of them
- The catalogue can now be used as a backup to the one found in the last slice (contains offsets in virtual file).
- The only information needed now is from the last slice to attempt a recovery

I have "emulated" something close to a standalone slice in the following way (using the stable release).  I create a sliced archive (5 slices), and I rename the 2nd and 3rd slices so that they are not found.  This leaves just the 1st, 4th, and last slices.  For each file in the original backed-up directory, I attempt a restore using "dar ... -g file".  The slicing scheme is retrieved from the first slice, and the catalogue from the last slice.  If the file in question resides completely in the 4th slice, then the restore proceeds.  Otherwise, dar asks me to provide the xth slice and I cancel the operation.  The end result is that I restore all the files in a single slice.

Now... you say that the new version would not require the first slice to get the slicing scheme.  So that takes us down to just the last slice and the 4th slice.  Furthermore, we don't really need the last slice in its entireity, but merely the catalogue and the slicing scheme that are encoded.  We can get the slicing scheme from the 4th slice and isolate the catalogue into a much smaller file.  So let's drop the last slice and replace it with the isolated catalogue.  That leaves just the 4th and the catalogue.  So far no changes in the code at all.  

My proposition is to replicate my "by hand" method above.  We try to restore all the files listed in the catalogue.  When a missing slice is needed dar should not prompt the user, but silently fail in the restoration and move on to the next file in the catalogue.  This could even be done with an external script providing that you could set dar to automatically exit rather than ask for a missing slice.  

A more efficient way would be to allow the catalogue to be trimmed to the contents of a specific slice.  That would eliminate the repeated attempts and failures, but it would require some extra code and would have to be regenerated in the event of a reslice.

What do you think?

Bill  

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