deja-dup issue

[Tony Arnold]

Colin,

On 16/05/16 16:25, Colin Law wrote:
> On 16 May 2016 at 14:37, Tony Arnold <tony.arnold at manchester.ac.uk> wrote:
>> Colin,
>>
>> On 16/05/16 13:42, Colin Law wrote:
>>> On 16 May 2016 at 13:27, Jatin khatri <khatri.jatin at gmail.com> wrote:
>>>> On Sunday 15 May 2016 12:55 PM, Petter Adsen wrote:
>>>>
>>>> On Sun, 15 May 2016 08:09:30 +0100
>>>> Colin Law <clanlaw at gmail.com> wrote:
>>>>
>>>> On 15 May 2016 at 05:07, Jatin khatri <khatri.jatin at gmail.com> wrote:
>>
>>>> One more question, Does it support Compression and Incremental backup ( same
>>>> like Deja-Dup)  ?
>>>
>>> Assuming that you mean backintime then no to compression.  If a file
>>> has not changed then hard links are used in the backup so that the
>>> unchanged file takes up (effectively) no space.
>>
>> Just to add to this. If the backups on a different file system to the
>> source, then copies are made. Or is that only for the first snapshot? Do
>> subsequent snapshots use hard links to the backed up version for
>> unchanged files?
> 
> The links are entirely within the backup. The first time a file is
> encountered it is copied to the backup, then later snapshots link to
> the copy.  So if you did a backup and then immediately backed up again
> then the second backup would be entirely made of links to the first.
> Then the backup device could be removed (if it were on a removable
> disc for example) and read on a different machine and all the files
> would be there in both snapshots.  That assumes the backup is onto a
> file system that supports hard links of course, otherwise backintime
> has to make new copies each time.  The backup can be to a different
> machine using, for example, ssh.

Thanks. That makes sense. Just started playing with backintime as
deja-dup gives weird errors now and again, so not too happy with it.

Regards,
Tony.
-- 
Tony Arnold, IT Security Analyst, University of Manchester.
T: +44 (0) 161 275 6093, F: +44 (0) 705 344 3082,
M: +44 (0) 773 330 0039, E: tony.arnold at manchester.ac.uk