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Re: Identifying which files changed between archives

I had the same issue a while back. I was told it was not easily fixed due to the layers in Tarsnap. I ended up making a regular tarball and fed that to tarsnap. That way I had a local tarball that matched the actual data in the archive. Then I could extract it and compere at the next backup. A bit data heavy process but it gave me what I needed. It is scriptable, so it is possible to let your backup script log the changed files on each backup run, but it has a pretty high cost in disk I/O, plus you need to keep a copy of your data around between backups.


On 18/06/2019 13.49, Scott Dickinson wrote:

I'm trying to work out how to generate a report on files that are new or changed in a particular archive. I can't seem to find an easy way to do this, so hoping someone can help.

Here is the scenario I'm working through.
1. Backup directory "x" on 1st May 2019. First time archive, all 10Gb are sent as expected. 2. Backup directory "x" on 1st June 2019. Second time archive, 25Mb are sent.

How can I report on which files that 25Mb of delta's are part of? In this scenario, I wasn't expecting any changes to the files over the month, so am surprised there were anything above the metadata to be backed up. My understanding is that Tarsnap needs to know which files the changed blocks belong to, therefore in theory this metadata should be extractable.

The closest I've found to locate this is "tarnsap -t -f 'x' -v --iso-dates", but this doesn't natively provide the details I'm after. Ideally I'd like tarsnap to be able to report which files were uploaded at the time or archive with an option similar to --print-stats.

Anyone got any ideas?