[kmp]

I moved much of my personal file storage off of my Macs to a server (in this case, running WebDAV); it's all worked really well for the most part.

With Lion, I've been very interested in the "Versions" feature - where applications like OG support what is apparently a Time Machine-like interface for browsing and recovering a history of changes to a file.

My research seems to indicate that this history is not in the file [bundle] nor is it attached in a way similar to the old resource forks. It's stored in a volume-specific database, apparently. (I've also seen reports that some of this data is stored in ~/Library, but I haven't found that location yet.)

What this means is that if it's copied to another volume (a process that some of us call "backing up") the version history goes away.

I'd be interested to know whether anyone has tried backing up versioned documents. or has any other ideas for retaining the document version history. It seems like great idea, and I suspect that Time Machine does manage to preserve versions, but other tools may not.

[Brian]

My understanding is that Versions and Time Machine go hand in hand - as you're working, the updates are getting saved to your Time Machine database.

[Brian]

Okay, it turns out that I'm not quite correct. Time Machine isn't required, but the location where that info is saved is not documented and isn't meant to be user-accessible. (Versions doesn't save the whole file - it saves individual chunks of the file that have been modified.)

So it doesn't look like Time Machine is required, but if you want to back up your Versions info, that's the only supported method of doing so at the moment.

[kmp]

Originally Posted by Brian

Okay, it turns out that I'm not quite correct. Time Machine isn't required, but the location where that info is saved is not documented and isn't meant to be user-accessible. (Versions doesn't save the whole file - it saves individual chunks of the file that have been modified.)

So it doesn't look like Time Machine is required, but if you want to back up your Versions info, that's the only supported method of doing so at the moment.

The volume database is at /.DocumentRevisions-V100 (right "next" to /.Spotlight-V100); my understanding is that the store is a SQLlite database. I have heard that there is data in ~/Library as well (and one explanation that is the principal reason for making that directory invisible), but I don't know where.

I noticed that iDisk's local cache (which is presented as a volume) will get a database, but again revisions are lost if te file is moved to it via the Finder.

Time Machine is a wonderful solution for an individual user, but in a corporate environment (especially a regulated one) it's problematic. NAS units have become popular to host Time Machine repositories, but that's using AFP and Lion uses a new version that's broken many of those implementation. Perhaps Mac OS X Server?