Makin' backups -- questions

David Christensen dpchrist at
Fri Jun 12 19:23:54 UTC 2020

On 2020-06-12 03:37, Ronald F. Guilmette wrote:
> In message <ef3ebee8-a3f1-8caf-040d-d9483afc5c15 at>,
> David Christensen <dpchrist at> wrote:

>> The simplest, but least efficient, backup method I have found for system
>> drives is to copy the device raw sectors to a file with dd(1)
> Too slow.

Fast enough for me:

         # time dev2img ...
         real    12m4.536s
         user    9m6.544s
         sys     0m48.416s

> rsync allows me to just update my backup drives incrementally, which is
> WAY faster.  (My server has 3TB live.  DD'ing all of that would take all
> night.)

See previous:

 >> 3.  I keep my system images "small" ...

>> 2.  I use MBR partitioning, to avoid problems with the GPT backup
>> partition table when the source and target device sizes differ.
> You're going to have to explain that one to me.  What are these "problems"
> of what you speak?

See "Secondary GPT":


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