Looking for application to clone a disk with incremental backup

[Cameron Simpson]

On 10Sep2015 21:43, Paul Smith <phhs80 at gmail.com> wrote:
>On Thu, Sep 10, 2015 at 9:06 PM, Joe Zeff <joe at zeff.us> wrote:
>>>
>>> For incremental backups, you could do something as simple as rsync or
>>> use one of the many backup utilities around (amanda, bacula,
>>> mondorescue, etc.).
>>
>> My personal choice is BackInTime because it's easy for me to set up and
>> manage, but it might not fit your needs.
>
>Thanks, Joe, for your reply. BackInTime seems to be a great backup
>tool -- I am going to give it a try --  , but I was looking for a
>cloning application (with differential /incremental backup).

Had you considered using a qcow2 disc image file? Stored on whatever your 
external drive is. Then for an incremental, just make a new .qcow2 which uses 
the previous one as a base, just as one does with VM snapshots. There must be 
some kind of tool which will read/write to a .qcow2 as an image: you'd then 
just need to do a "sparse" disc copy to the new incremental .qcow2 i.e. read 
your source drive in blocks, read the .qcow2 in parallel, only write changed 
blocks to the qcwo2.

Regretably (appallingly), last time I looked there was no facility to attach 
such an image as a block device, which would make all of this trivial (not to 
mention many other things).

Would be happy to hear if things had improved.

Cheers,
Cameron Simpson <cs at zip.com.au>