Backup questions

I use Arq for backup and I have always found myself very well. For some time, however, I have noticed that even if I have the databases open, it only backs up the sparseimage files. How come? altar question: always with Arq as I think it applies to any type of backup, is it better to back up an open database or is it not a problem to do it of an encrypted database, that is, a sparseimage?

This topic discussed before and there are different views (based on perceived risk, I guess). Me:

  • I would always assume a Time Machine or Arc backed up while the database is “open” might not be up to date. Sort of depends on what happens in DEVONthink during the backup process (which DEVONthink does not control in any way whatsoever). Some people may say other, but that’s just me. Hurts my brain to think about it harder, especially since there are other ways to reduce my risk than trying to bend DEVONthink and backup software to my will.

  • that being said, I still do not exclude DEVONthink databases from backup. And I normally close all DEVONthink databases at the end of the day so the machine has 12 hours to “catch-up” with good backups (assuming machine left on). So if I need to restore, I’d look at the TimeMachine backup from the middle of the night when I know databases are closed. If no good, I go to option 2 (below).

  • I have a scheduled CRON job that does a DEVONthink “Daily Backup Archive” for all open files 3 times a week, directed to the ~\backups\DEVONthink\ folder. I made this change to a copy of the DEVONthink version of this script to put it in a different folder than default, and to make it schedulable with CRON. TimeMachine (or it could be Arc) backs up that folder. This folder also syched “on change” into a Synology NAS clone of this folder holding zipped backups.

  • Backblaze also backing up all this stuff.

Overkill? Probably. But all automatic so no bother.

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DEVONthink’s encrypted databases open as sparseimage files to avoid a specific issue caused by Time Machine unmounting the .dtSparse file.
While it is ideal to back up databases when they’re closed, life and work isn’t built for ideal conditions so backing up while they’re open is acceptable.

Also, you can look at your backup schedule.
I do an incremental backup once a day, at 9:00pm (21:00) since I’m not usually working at that time. Sometimes DEVONthink will be closed, more often not, but the databases won’t be in active use when the backup runs.


As opposed to the (individual) content of the bundles, you mean? AFAIK the OS does that - it’s the same if you copy an open sparseimage to a new location: the new location contains a closed (encrypted) bundle. I love that - it means my DT data never leaves my device unencrypted.