Restoring and snapshots

[Andrea Venturoli]

On 2020-04-12 00:18, David Christensen wrote:

> I am confused:
> 
> *  What is the type of the filesystem that was the source of the backup?

ZFS in the example above, but I've got the same problem with UFS, as I 
also use snapshot there.



> *  What tool(s) did you use to backup?

Sometimes Bacula, sometimes some custom scripts.



> *  What is the type of the filesystem that was the destination of the 
> backup? 

Could be UFS, bacula volumes, tapes, ZIPs, etc...



> *  What tool(s) are you using to restore?

Again either Bacula or some custom scripts.




> *  What is the type of the filesystem that is the destination of the 
> restore?

Usually UFS or ZFS; could be something else.



> So, the backup source filesystem and the restore destination filesystems 
> are both ZFS (?).

Possibly, but not always.



> The upper Unix filesystem path should be an empty directory.

Should, but not always is.
Sometimes I found "forgotten" files in the directory which is the target 
of the nullfs mount. Of course those files are usually hidden and 
probably useless, but must be taken into account.



> I believe it is a result of the 'mountpoint' properties of the two ZFS 
> file systems and how ZFS represents filesystem snapshots in the Unix 
> file system.

No, this can happen with UFS too.




  bye & Thanks
	av.