Comment 27 for bug 875676

I have some further details about this bug! Not super positive, but still.

First, I'm going to mark bug #676767 a duplicate of this. That's a slightly older bug with the same symptom, and a workaround (of deleting the cache) that doesn't seem to work in all cases. But ultimately, it's indistinguishable from this, so I'll dup it.

Second, I was recently helping a user that was affected by this. They were on Ubuntu 14.04 moving to 16.04 (meaning a backup made with duplicity 0.6.23-1ubuntu4.1 and deja-dup 30.0-0ubuntu4.1, trying to restore with duplicity 0.7.06-2ubuntu2 and deja-dup 34.2-0ubuntu1.1).

After investigating it with them, we found that many (100s!) of their volume files (size 50mb) were all zeros. That is, not valid gzip files but just a file full of zero-bytes.

Other files seemed corrupted in a different way (not valid gzip, but not all zeros either). There were less of these.

They did not use encryption. They stopped and resumed the backup a few times. It was altogether a single full backup.

I don't know what to do with this information. But there it is.

I note that we don't see this often anymore? The latest report here is from 18.04, which would be duplicity 0.7.17-0ubuntu1.1. It may be too optimistic to hope that it's solved now. But certainly less common than it used to be, I think?