It was World Backup Day yesterday (I have so many questions). I missed it, but the concept is probably still valid today.
Why not take a moment to consider how your databases have grown since you started using DEVONthink? To think about how important the data kept in those databases is to you personally. What loss of that data would entail - time lost, money lost, clients lost? Memories lost? Maybe check whether your own backup strategy has kept pace with a changing world - are you threatened by the elements, loss of power, loss of mind, loss of life, theft, fire, decay? Do your children get to play with your Mac? Have you moved to home office, keeping records at home? Does your backup strategy reflect the value of your data and the risks you might reasonably be exposed to? Have you tested it?
Sometimes I test clone drives by booting from them. However, I don’t really test non-bootable backups, apart from checking that everything that should be backed up is actually included in a first test run.
Now searched for “ChronoSync test backup” and found this:
What kind of tests should you perform? First, review the files that are in your backup and make sure that all the files you expect to be there, are really there. Next, randomly choose some of your more important files, restore them to a temporary folder, and then verify that those restored files are intact. And finally, if it’s a bootable backup, then make sure that you can actually boot from it. That’s all there is to it!
But some time ago I found out that a scpt file was corrupted - and it was far too late to restore it from a backup. The script wasn’t important but since then I’m afraid that corruption could happen to important files - without noticing it. Any idea how to prevent that a file gets corrupted without being aware of it?
For records within DT I use a checksum script, run daily, which I assume would alert me to any corruption early in the game. But I also back up DT databases to WORM media, so I would hope that any data loss I note within the lifespan of that media (5 years? 10?) would be mitigated.
For records not in DT, I have no solution. But as I don’t store anything of any permanent importance outside DT, I hoping I’ll be ok.
The script will make me aware of any changes to locked files (so even unintentional editing), which DT itself can’t (which is perfectly reasonable). Obviously it also flags intentional editing - but generally, I have no intention of editing a locked file (files are locked by scripts immediately in some cases, and after a delay in others).
One of the reasons why I count on handcrafted backups which are valid & verified (e.g. databases or sources) before archiving them. And the archives date back several years. The automatic backups, e.g. Time Machine, are just an additional measure. Therefore there should be always at least one working copy.
My assumption is that that must depend on the kind of corruption; a damaged file would be detected by DT, a changed file presumably not. So if you were, e.g. to open a script and inadvertently delete part of it, then DT would have no way of knowing that that was unintentional (this has been criticised by users in the past, with some suggesting a locked file should be just that: locked); my script would flag that file. Obviously this is only useful for files which are not regularly changed - which, for me at least, is the case for locked files.
In addition to my backups to SSDs and online, I perform a once-monthly backup to WORM media. This is the only backup which I store ad infinitum; all other backups are overwritten in time (oldest first). Storage ad infinitum* should mitigate against late recognition of loss or corruption. My choice of WORM media is to mitigate against possible (and especially dormant) malware - instead of plugging in an external drive (which might already contain e.g. 2 years worth of backups) every so often, I produce a disc which cannot later be altered and is basically only ever brought back on site for testing or if required for restoring. To an extent, I’m also hoping to mitigate against technical failure (i.e. better to have 20 discs than 1 drive) - as WORM discs age, however, I’m not sure that decision holds water.
* ad infinitum is overly optimistic, of course; I haven’t yet decided what to do when I feel the media have reached their lifespan. Based on the price of SSDs, I may decide to copy every disc to a single SSD say every 5 years.
I‘m having a hard time imagining that happening unpredictably. I‘m expecting it to happen when the owners and programmers at DEVONtech become aged, and decide that recompiling their software for macOS Black Depths on a 76-bit LEG processor is too much effort. I can‘t envisage a situation where DT becomes irreversibly unavailable from one moment to the next; I may, however simply lack imagination, und would appreciate prompting. Currently I work on the assumption that walking back a macOS or DT update, or changing the system clock would reverse anything which could happen spontaneously. As I own two macOS devices, I delay updating both DT and macOS on the second device until I have run DT once on the updated device.
The records are actually always accessible within the databases, even if retrieving it from there may be strenuous, and you would certainly lose any database structure.
As such, I currently don‘t produce DT-agnostic backups; I look forward to feedback here, and may reconsider. My monthly backup to WORM would, of course, be an ideal point in time for a DT-agnostic backup. In the past, I have put that idea aside, as I would need to add an additional layer of security; my databases are encrypted, so copying them to WORM media means the data on that media is protected without further steps.
I’m going to go ahead and answer my own question here: my place burns down, and I escape with my life, leaving all my iDevices to perish. I don’t live-stream my escape to social media. The next few days are difficult: all my documents are gone, my IT is destroyed, and the only thing I have are my off-site backups. None of my friends are as posh as I am, and all only own PCs - so I’ve got a database which I can’t adequately access. If it were DT-agnostic, then I could get at those insurance documents, that birth certificate etc. on a friend’s PC. Then the bank would believe me, deliver me a new credit card, and I could at last purchase a new Mac.
So, I will add a once-monthly DT-agnostic backup to an encrypted SSD to my backup strategy. Does that make sense?