Re: Using rsync to disk on the system being backed up?

On February 15, 2023 7:41:25 PM UTC, [email protected] wrote:
>On Wednesday, February 15, 2023 01:24:16 PM [email protected] wrote:
>> rdiff-backup (rdiff is something different) actually uses the
>> patching/delta approach of (lib)rsync also locally to store less data.
>
>I guess I should have given more context (or clarity) to my questions.
>
>Part of my question was intended to be: if I don't have rdiff-backup available 
>(for whatever reason), can I use fairly standard tools (e.g., patch) to 
>retrieve older versions that I've backed up.

Short answer: no.

>
>If rdiff-backup is storing less data, maybe it is not enough for patch to work?

Patch is only for text files, we're talking any kind of files, also binary ones.
>
>If that is not the case (if rdiff-backup) is storing data just like would be 
>created by a fairly standard (reverse) diff (of whatever flavor, e.g., unified or 
>whatever), I don't see any benefit to using something like rsync to communicate 
>with a disk on the same computer (for the case when I am backing up to a(n 
>internal or external disk) on the computer being backed up.

Forget about rsync, this is confusing you.

KR, Eric
>
>> On 15 February 2023 19:16:50 GMT+01:00, Robert Nichols 
><[email protected]> wrote:
>> >On 2/15/23 10:35, [email protected] wrote:
>> >> I've googled enough to find out that rdiff at least in some
>> >> circumstances uses rsync to minimize communication bandwidth.
>> >> 
>> >> My question is this: if rdiff-backup is backing up to a disk (internal
>> >> or external) on the machine being backed up, does it continue to use
>> >> rsync?
>> >
>> >When working over a network link, rdiff-backup works in a manner _like_
>> >rsync. It doesn't actually use the rsync program. When backing up to a
>> >local disk, it of course accesses the disk directly.
>> >
>> >OK, I suppose if you really wanted to simulate networked operation when 
>working locally you could run:
>> >    rdiff-backup backup {source directory} localhost::{archive directory}
>