Re: fsck required after startup on Mac

[Graham Percival <gperciva@tarsnap.com>]

Hi Federico,

Tarsnap automatically skips archiving the cachedir, but there's certainly no
harm in omitting it from your archived directories.

I think that in your case, if the cachedir changes, then that indicates
something weird.  The cachedir can change as a result of certain tarsnap
operations (such as deleting an archive), but if you don't have an automatic
backup process, I would hope that you don't have an automatic archive deletion
process!

In case you haven't seen it, here's some additional info about the cachedir:
https://www.tarsnap.com/cachedir.html

Sharing the ls -l from your cachedir on this list is not necessary; I would
only send that as a private email to me and Colin.  The size of the
"directory" file indicates how many blocks you have stored on the tarsnap
servers.  Due to deduplication, that doesn't reveal a huge amount about your
backups -- it would be impossible to tell if you had a few large archives, or
many deduplicated small archives -- but it's still private info.

Cheers,
- Graham

On Sun, Sep 18, 2022 at 01:35:55PM +0200, Federico Pereiro wrote:
> Hi Colin and Graham -- thank you for your replies!
> 
> Indeed I've never set up an automatic backup process, and list-archives
> (thankfully) shows no surprises. My cachedir is inside an encrypted
> container and outside /tmp. Also, I do not back it up on Tarsnap (in case
> that changes things, although it probably shouldn't).
> 
> To my great surprise, I just managed to create an archive after restarting
> (bugs do have a tendency to become shy when attempting to replicate them).
> I'll make sure that I save the output from ls -l and the shasum of cachedir
> after every backup, to see what could the issue be. I'd gladly share the
> output here, but I don't know if it's wise to do so from a security
> perspective.
> 
> Just that I understand 100% correctly, the cachedir should only change
> whenever I run an archive, right?
> 
> Thank you!
> 
> чт, 15 сент. 2022 г. в 21:06, Colin Percival <cperciva@tarsnap.com>:
> 
> > On 9/15/22 11:18, Graham Percival wrote:
> > > 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.
> > The other possibility which comes to my mind is that MacOS might be
> > deleting
> > the cache directory when you reboot.  You don't want to put it into /tmp/,
> > for example...
> >
> > --
> > Colin Percival
> > Security Officer Emeritus, FreeBSD | The power to serve
> > Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid
> >