[tahoe-dev] interrupting tahoe backup

[Brian Warner]

Jody Harris wrote:

> Can I just hit Crtl-C to interrupt a tahoe backup command and then
> restart it later without consequence?

Yes.

The second run should skip over all of the uploads that were completed
by the (partial) first run, so you don't lose very much progress by
interrupting it (at most a single file's worth of upload effort).

> I interrupted the backup so that I could use my computer. I have an at
> qued to run it tonight.

> 1) Is there a tahoe restore, or is it just a matter of copying the
>    files back to the local machine for restoring?

The latter. There is no "tahoe restore", just use "tahoe cp
ALIAS:blahblah/Latest/subblah localdir". You can copy out whatever
portion you care about, from whichever snapshot you like.

> 2) After running backup for several hours, it looks like ~50 files
>    were copied to the grid. When I list the backup directory, the only
>    item shown is a directory named "Archive." no other files are
>    listed. Where are my files?

The top-level "Latest" link won't be added until the very end of the
run, so from the point of view of the directory in which you're storing
the snapshot, there are no side-effects of a partial backup. The
intention is that "tahoe backup" makes an atomic change to your tahoe
filesystem, adding exactly one complete snapshot per complete run.

Your backupdb should currently remember filecaps for the 50 files that
were uploaded. On tonight's "tahoe backup" run, it will skip over those
50 files and start uploading the 51st. It will also record an
immutable-dircap for each directory that it finishes processing. Until
the backup completes, these filecaps and dircaps will only be remembered
by the backupdb. Once the backup completes, they'll be reachable from
the backup target (via the "Latest" link, or the timestamped snapshot
link).

cheers,
 -Brian