Question re: incremental backup and directory rename detection

[Mike Cappella-2]

I'm curious about how tar is determining directory renames in
incremental backups.  Is this by inode number, and the messages below
are informative only?

 From a strict name-only point of view, the rename detection below is
incorrect (names of IMAP directories "new", "cur", and "tmp", after
rename of any parent directories, would remain the same):

gtar: .../Maildir/.Archives/cur: Directory has been renamed from
`.../Maildir/.Archives.2009/new'

gtar: .../Maildir/.Archives/new: Directory has been renamed from
`.../Maildir/.Archives.2009/tmp'

gtar: .../Maildir/.Archives/tmp: Directory has been renamed from
`.../Maildir/.Archives.2009'

If the messages are simply informative that the name previously
corresponding to the inode is different across incremental backup runs,
it seems there's nothing to worry about?

If you could help clarify, I'd appreciate it.
Thanks
--

      Mike

[Sergey Poznyakoff-2]

Mike Cappella <lists-general@...> ha escrit:

> I'm curious about how tar is determining directory renames in
> incremental backups.  Is this by inode number, and the messages below
> are informative only?

Yes, it uses the inode number. If the inode number is the same as
stored in the snapshot file, but the file name has changed, then
this file is called "renamed", for purposes of incremental dumps.

> From a strict name-only point of view, the rename detection below is
> incorrect (names of IMAP directories "new", "cur", and "tmp", after
> rename of any parent directories, would remain the same):

Perhaps, but from tar's point of view that's ok. Otherwise, it would
have archived the contents of .../Maildir/.Archives/{cur,new,tmp}
over again, even if there were no new or changed files in it.

Regards,
Sergey

[Mike Cappella-2]

On 8/27/2009 10:30 AM, Sergey Poznyakoff wrote:

> Mike Cappella ha escrit:
>
>> I'm curious about how tar is determining directory renames in
>> incremental backups.  Is this by inode number, and the messages below
>> are informative only?
>
> Yes, it uses the inode number. If the inode number is the same as
> stored in the snapshot file, but the file name has changed, then
> this file is called "renamed", for purposes of incremental dumps.
>
>>  From a strict name-only point of view, the rename detection below is
>> incorrect (names of IMAP directories "new", "cur", and "tmp", after
>> rename of any parent directories, would remain the same):
>
> Perhaps, but from tar's point of view that's ok. Otherwise, it would
> have archived the contents of .../Maildir/.Archives/{cur,new,tmp}
> over again, even if there were no new or changed files in it.
>
> Regards,
> Sergey

Excellent.  Thanks for the clarification and your time.

--

      Mike