[pbs-devel] [PATCH-SERIES v4 pxar proxmox-backup proxmox-widget-toolkit 00/26] fix #3174: improve file-level backup

[Fabian Grünbichler]

On November 13, 2023 4:14 pm, Christian Ebner wrote:
> Thanks for your comments, some thoughts inline:
> 
>> On 13.11.2023 15:23 CET Fabian Grünbichler <f.gruenbichler at proxmox.com> wrote:
>> some (high-level) comments focused on compatibility:
>> 
>> the catalog v2 format is used unconditionally at the moment. IMHO it
>> should be guarded/opt-in via --change-detection-method, since old
>> clients cannot parse it.
> 
> While it is true that the new catalog format is not readable by an old client,
> the motivation to include this unconditionally was to be able to also use
> backups created with the default change detection mode as reference.
> Backups with the change detection mode set to metadata would still not be
> readable by older clients.
> 
> I can of course make this conditional and only ever use catalogs with format
> version 2 as reference in cases of metadata based file change detection.

IMHO the downside of requiring two runs for the change-detection to
become effective (which is the case for new groups anyhow) is far
smaller than unconditionally breaking all catalog-related features for
older clients with no way of opting out. especially since some of those
features are server-side (file browsing/download for unencrypted
backups, for example), and you might have a mix of clients accessing a
PBS repo. the first run that just changes the catalog format to support
subsequent runs could easily detect and log this state prominently to
avoid confusion.