Re: "tarsnap: Cannot store file: File already exists"

[Colin Percival <cperciva@tarsnap.com>]

On 05/29/11 03:23, Colin Brace wrote:
> I run tarsnap on a daily basis like this: 
> 
> tarsnap --humanize-numbers -c -f myhost-$(date "+%Y%m%d") /var /etc
> /usr/local/etc 
> 
> Several days ago, I started getting an error message:
> 
> tarsnap: Cannot store file: File already exists
> tarsnap: Error closing archive
> tarsnap: Error exit delayed from previous errors.

Huh, that's an error I didn't expect anyone to ever see.

> It doesn't appear to be the archive name that is causing problems. So what "file" is this referring to?

The "file" here means a block of encrypted compressed deduplicated data being
uploaded to the Tarsnap service.

This error means that the Tarsnap client code is trying to upload a block and
the Tarsnap server is sending an error back saying "I've already got that" --
i.e., the deduplication is failing.  This means that your cache directory has
somehow gotten out of sync with the server (normally the client code knows
exactly which blocks are on the server), which is impressive since the client
code works very hard to prevent that from happening.

Have you done anything odd with the cache directory?  Have you had a system
crash which could have resulted in filesystem corruption?

-- 
Colin Percival
Security Officer, FreeBSD | freebsd.org | The power to serve
Founder / author, Tarsnap | tarsnap.com | Online backups for the truly paranoid