Re: fsck required after startup on Mac

[Graham Percival <gperciva@tarsnap.com>]

Hi Federico,

My first thought: do you have a computer (or user account) that you forgot
about?  For example, you might have an ubuntu server that's faithfully making
an archive every night using the same keyfile as you're using on your MacOS
machine.

That's a very unlikely theory, but it's easy to check: take a look at
tarsnap --list-archives and see if there's an unexpected archives there.
(Also, in this scenario, your ubuntu server would be automatically running
--fsck before making the new archives).

Assuming that's not the case, I would try making a copy of your cache
directory, or at least recording the directory listing.  For example,
right now my casual "garbage test tarsnap" cachedir is:

$ ls -l ~/.test-tarsnap/cache/
total 76
-rw-r--r--  1 td  td    103 May 13 12:26 cache
lrwxr-xr-x  1 td  td     64 May 13 12:26 cseq -> 5c10f4d39bc2508073a02cc8710821800f5f970d1255497f53d493e58dc399da
-rw-r--r--  1 td  td  72264 May 13 12:26 directory
-rw-r--r--  1 td  td      0 May 13 12:20 lockf

If I checked that in a day or two and found different dates and cseq (without
myself consciously making a new archive), that would be very weird.

I also mentioned making a copy of that directory (on a different storage
device).  My thinking there is that if your hard drive is randomly flipping
bits -- or worse, if your system is currently compromised by somebody setting
you up for a ransomware attack -- then the contents of that directory could be
changing, without the file sizes or modification times changing.  To
investigate this possibility, I'd try copying the cachedir to a different
computer or USB drive; wait a day; then compare the contents with sha256sum.

Cheers,
- Graham

On Thu, Sep 15, 2022 at 08:55:27AM +0200, Federico Pereiro wrote:
> Hi Graham, Colin & list,
> 
> I'm experiencing an issue where every time I restart my computer, Tarsnap
> requires me to run fsck when I create a new archive:
> 
> tarsnap: Sequence number mismatch: Run --fsck
> tarsnap: Error creating new archive
> tarsnap: Error exit delayed from previous errors.
> 
> Previously, when using Ubuntu, this would only happen when I had network
> errors during the archiving process. Now, it happens after every restart,
> despite experiencing no issues during archiving. I'm using MacOS 12.6,
> using Tarsnap 1.0.40. I have FileVault enabled and I also use
> Truecrypt/Veracrypt volumes (not sure if any of that makes a difference).
> 
> Any suggestions about how to debug this?
> 
> Thank you!
> Federico