Re: two machines, same key

[Colin Percival <cperciva@tarsnap.com>]

On 4/4/25 08:26, John Doherty wrote:
> Hi, yesterday I made a mistake and I'm not sure how to fix it without 
> resorting to --nuke (which would not actually be catastrophic).
>
> I have one machine, let's call it A, that has been running tarsnap from cron 
> for a pretty long time. Yesterday, I made a replica of this machine, B, 
> without stopping to think about the implications for tarsnap. Since B is 
> mostly a replica of A, they both have the same keys (it's not strictly a 
> replica: they have different IP addresses and hostnames).
>
> They both tried to run tarsnap at the same time. B succeeded and A failed with 
> "tarsnap: Sequence number mismatch creating checkpoint: Run --fsck", which is 
> understandable.
>
> The current state of affairs is that B can run tarsnap --fsck but A cannot. If 
> I try, A reports:
>
> tarsnap: Sequence number mismatch creating checkpoint: Run --fsck
> tarsnap: Error fscking archives
> tarsnap: Error exit delayed from previous errors.
>
> The desired state of affairs is that A can run tarsnap again and B does not 
> need to. I've disabled the cron job on B, so it won't run again unexpectedly.
>
> Not sure what to do. Maybe rename the tarsnap-cache directory on A and let it 
> create a new one?

Easiest option here is probably to delete the tarsnap-cache directory on A and
copy the tarsnap-cache directory from B over to A.

The other option is to delete the directory and run `tarsnap --fsck` to create
it again; but that involves downloading metadata from the tarsnap service so
there's not much point doing that when you already have a copy of everything
on the B system.

--
Colin Percival
FreeBSD Release Engineering Lead & EC2 platform maintainer
Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid