ZFS snapshots and daily security checks

[Jeremy Chadwick]

On Mon, Apr 08, 2013 at 12:50:02PM +0400, Lev Serebryakov wrote:
> Hello, Jeremy.
> You wrote 8 апреля 2013 г., 12:07:38:
> 
> JC> I don't know what to tell you -- my output clearly shows that after
> JC> creating a snapshot with "zfs snapshot -r filesystem at snapname" that
> JC> mount nor mount -p show anything.
>   What's  really wander me, why is here difference between `mount' and
>  `mount -p' output on my system. It looks like `-p' option should be
>  cosmetic one...
> 
> JC> I wonder if you have either pool or filesystem-level attributes which
> JC> are causing your issue.
> 
> JC> Here are mine, for the pool and filesystem I used in my previous mail
> JC> (pool "data" and filesystem "data/home"):
> 
> JC> data/home  snapdir               hidden                 default
> pool/home  snapdir               visible                 default
> 
>   It is only not size- and date-related difference. So, we know why
>  here is difference between my and your `mount -p' outputs! (BTW, why
>  both values are default?!)

And what about the properties for the filesystem called "pool" (yes,
I said filesystem, and I mean it)?

My theory is that your "pool" filesystem has the snapdir property as
visible, and therefore all filesystems under pool (ex. "pool/home")
would inherit the value.

Looking at the ZFS code, hidden **is** the default, even in r244958
(which you're running):

http://svnweb.freebsd.org/base/stable/9/sys/cddl/contrib/opensolaris/common/zfs/zfs_prop.c?view=annotate

See line 218.  The 3rd parameter, ZFS_SNAPDIR_HIDDEN, is what defines
the default value.

-- 
| Jeremy Chadwick                                   jdc at koitsu.org |
| UNIX Systems Administrator                http://jdc.koitsu.org/ |
| Mountain View, CA, US                                            |
| Making life hard for others since 1977.             PGP 4BD6C0CB |