I’ve been using DT since, IIRC, DTnotes in 2004 but I remain unclear in general about Devonthink’s backup strategies. This question specifically regards how DT interacts with Time Machine.
There seems to be no confusion as to whether Time Machine will backup the entire database package but it is unclear to whether Time Machine will look inside the package of the database and only backup the changed files within. Further, I can’t tell if such an incremental backup will be properly restored as a coherent DT database.
Based on my recent experience, I believe Time Machine is trying to backup the entire package when even the smallest change is made.
Problem Story: In the past my DT databases where fairly small and mostly text files but after I decided to use tagging heavily, I moved gigs of data inside of various DT database (probably the majority of my work data) so that now some are in the tens of gigs in size. I used a combination of Carbon Copy Cloner and a custom unix kludge but neither were network based and I had an increasing tendency to forget to maintain them after moving to a laptop.
After a drive failure on the laptop, I decided to switch to Time Machine for its automatic nature and easy support for laptops.
I had problems backing up initially which led me to discover a failing hard drive. I cloned drive with CCC and then had the drive swapped out. I thought I had fixed the problem.
But while twice attempting an initial backup of a single drive of 230gb, I left it running overnight via direct ethernet and in the morning the backup reached the around 225gb and said it had only about 15minutes to go. Thinking everything was fine, I opened DT to do some work and 30 minutes later noticed that the Time Machine was still running. Only now it reported that it had backed up 235gb with ~250 pending. Worse the size of the pending continued to grow. The estimated time remaining always said “5 seconds.”
Using opensnoop and rwsnoop on backupd I saw that it was churning through and copying the entire DT databases I had opened. Since these databases were multigigabyte in size, backupd was trying to copy another ~30gb and, apparently tried to do so again, whenever I made the least change. Clearly, this was untenable in my case.
This has become a rather serious problem for me because I centralized perhaps the majority of my data inside DT, especially vital small notes and snippets, that I must backup on a continuous basis. If Time Machine can’t work with DT, I need to rethink my entire backup strategy.
So, does Time Machine incrementally backup DT database packages or not?
If not what is the recommended solution for incremental e.g. hourly, backups over network for laptops?