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Data corruption on backup files

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(@pup_seba)
Posts: 11
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Hi,

In regards of this other post https://forums.zextras.com/zxbackup/1810-unkown_folders-during-backup-restore-operation.html

1) When performing a "zxsuite backup dosmartscan deep true", over an already set of backup previously obtained by "zxsuite backup dosmartscan", how this will behave?
a) Will the "deep true" force to re-write all the information?
b) Will the "deep true" check coherency of all the data already in the backup files and only write new information/update/correct broken data?

2) How can we detect corrupted data in a copy set of our backup? As for our experience, not all the errors show up in the logs and then we found "by surprirse" that there is corrupted data only after restoring such data.

3) How is different a "deep scan" from a non "deep scan" in terms of performance impact for the server and time it takes to complete?

4) When data corruption exists in the backup copy, we confirm data performing a "deep scan" will fix such corrupted data. Is this behaviour also expected by performing regular "smartscans" with the deep option set to "false" or only way to fix corrupted data in the backup set is by performing a "deep scan"?

These questinos come to us as sadly, we noticed that there was data corruption in our backup set only after restoring it. Thing is that all tasks showed "ok" status, but reality was that:
- Some folers for some users got copied as "UnknownFolder"
- For those users, not all the items were copied. We are talking about less than 1/4 of the itmes got copied

This happened to 10 users out of ~2.500. So even during periodic test restore operations, this is hard to spot or even by manually counting items and mailbox size of cherrypicked users. Logs (zextras or zimbra) show that everything was ok. Maybe there are more errors going undercover or maybe items are not fully copied also to users that do not have "unknownfolders".

Any info is welcome.

 
Posted : 10/03/2018 10:38