Incremental backup - force full backup
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Hi!
There are two options to force full backup when creating incremental backups:
It would be good if it was possible to use zstd with these options, just like it is for regular backup jobs:
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Hi,
This is not possible to mix compression with delta backup, at least at the moment.
Unlike "normal" backups (XVAs) we have to read and mostly write blocks inside the full to do the merge. So it means, at some point, uncompressing the full to read/write inside it, then re-compress.
This is sub-optimal.
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Understood. It would be good for the future though. Could it be handled separately like the normal backups are done?
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But how to coalesce the oldest delta into the merge then? This will require to decompress the whole full
This is a bit defeating the purpose of compression. -
olivierlambert said in Incremental backup - force full backup:
But how to coalesce the oldest delta into the merge then? This will require to decompress the whole full
This is a bit defeating the purpose of compression.Ah I see. Forgot about this. So the "full" in a delta backup means a new base image to base the next incrementals on? I understand then that it will not be possible to compress this type of full backup. I had thought it was similar to an independent full backup, which of course isn't the case. Thanks.
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That's correct. It's the new "reference" for the following delta, so we need to be able to read the full when we restore the backup (or a file) or when we coalesce (when reaching the retention).
That's why compressing the full isn't trivial.
