Incremental Backup State

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#1 Wed, 09/18/2013 - 12:32
eddieb

Incremental Backup State

I have one backup task that is incremental and another backup task that is full. "inc" runs daily but sunday. "full" runs on sunday.

if i manually run "full" one-off, let's say on a friday, but i edit the task before running it to backup to a DIFFERENT ocation (then leave the task as it was before this one-off run), does that reset the incremental state? As in, if I dont chose "Backup Level: Neither" i'm throwing the backup state tracker off?

ALSO

I know that on Virtualmin, restoring a incremental from wednesday automatically restore the prior incrementals (monday, tuesday) and the full one. Is the option to do this something considered desirable for the future?

Thanks

Thu, 09/19/2013 - 06:50
Locutus

I'm not 100% sure, but as far as I know, the incremental function works by comparing the timestamp of each file that's to be backed up against the timestamp of the last full backup that's in the same location as the incremental schedule. So by doing a full to a different location, you wouldn't influence the incremental.

Re: "ALSO": It does not per se automatically restore the incrementals from previous days, but in fact what VM calls "incremental" is actually "differential". I.e. it backs up all files since the last full, not the last incremental. Whether or not this is desirable is open to debate. I personally would prefer true incremental as well, since it can drastically reduce backup size. But it'd also be harder to implement, or require more manual work, and is less robust because you need ALL intermediate incrementals.

Thu, 09/19/2013 - 12:12 (Reply to #2)
eddieb

Thanks Locutus.

"works by comparing the timestamp of each file that's to be backed up against the timestamp of the last full backup that's in the same location". It makes sense that is how it works, and it would be nice if someone Andrey or someone else could confirm this is the case.

"what VM calls "incremental" is actually "differential"". As a matter of personal preference, I rather go for "differential", which allows for faster restores (space is so cheap these days). Again, it would be nice if someone Andrey or someone else could confirm this is the case.

Sat, 09/21/2013 - 14:09
eddieb

It would also be nice to allow encryption before sending. S3CMD has the capacity to do this.

Mon, 09/23/2013 - 09:05
andreychek

Howdy,

There is indeed an option to encrypt backups. If I recall correctly, I think that's a Virtualmin Pro only feature... but to determine that, if you look in Backup and Restore, do you see a "Backup Encryption Keys" option?

-Eric

Mon, 09/23/2013 - 09:25
Locutus

It's Pro only, indeed. I see that option in my Pro installations, but not in GPL.

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