Routine back-up question
I am relatively new to Zotero and am regularly backing up my data after each update to the library. I am backing it up from Dropbox (my regular data directory) to an external hard drive that I have locally. I noticed in the documentation that, under the "restore" section, it says, "If you have a local Zotero library that you want to overwrite, close Zotero and delete the old Zotero data directory before syncing." This guidance applies only to restoring, correct? For routine back-ups, I need only copy the parent Zotero folder (including all subfolders) from my regular data directory to my external hard drive, where it will override the old version from the last back-up. Or, do I need to delete the old copy before backing up each time? Thanks in advance for setting me straight.
Second, to backup your database manually, you need to copy out the contents of your data directory folder (instructions here: https://www.zotero.org/support/zotero_data#backing_up_your_zotero_library). The easiest way is to just use Time Machine or similar software to backup the entire folder. If doing it manually, just overwrite the old backup--you don't need delete the old copy first.
Third, you should generally not use the restore functions unless explicitly told to do so by someone on these forums. They aren't really intended for general use or troubleshooting. You are correct that that function is really only intended for wiping out problems in a local library by overwriting it with whatever is stored on the server.
To answer your question about Dropbox, I chose it simply because that is what I use for records management, generally. Given their security and the fact that they hold deleted records for several weeks before permanently deleting them (should I accidentally delete something), I thought it was a good choice. Apparently not. My goals are simple. I'm a doctoral student, so I merely want to be able to easily reach my library whenever I need to and to feel secure that it is regularly backed up. So, yes, please recommend a better setup than Dropbox.
Let me also say that I absolutely love Zotero so far. There are other research data managers out there but nothing as complete as this one. My university has promoted RefWorks, but for the life of me I can't figure out why. It's ok for reference management, but nothing like Zotero, particularly for organizing notes.
So, thank you again, and let me know what you think about a Dropbox alternative.
What you'd want to do instead of Dropbox depends on your requirements and the size of your library. There are basically four solutions. All of them involve syncing your metadata with Zotero (which is free regardless of the size of your library). To sync files you can:
1. Use Zotero file storage (easiest, most convenient, but costs for >300MB)
2. Use a third party webDAV (still very convenient but you need to find a reliable provider; also no easy access to files without Zotero installed)
3. Use ZotFile (www.zotfile.com) to turn attached files in to linked files in your Dropbox folder and sync with that (more set-up to work on multiple machines and no access to files via zotero.org)
4. Put a symbolic link to your storage folder into Dropbox (similar to 3. in effect, though may still cause some file sync conflicts when used on multiple machines, I believe; these aren't a huge deal, though, compared to database corruption, which is the problem with putting your data folder into Dropbox)
You can find instructions for all of these on the forums and in various blogposts.
Regular syncing (either using Zotero file storage or one of the other methods adamsmith listed) combined with an automated backup of your system on an external hard drive should be all that you need.