Keeping 2 external hard drives in sync

[jdiamond]

Hi everyone. I have a slightly different use case, and i wonder if any software yet exists to do this? The motivation is right now it costs $1,000 to go from a 4TB to an 8TB laptop SSD drive. So it would be great if I could do the "dock" thing - have external drives at home, work, and in between to use for less commonly accessed stuff. BUT - I need to keep these drives in sync, even though the drives are never in the same place at the same time.

So what software would have to do is on my own laptop, track any changes I've made to an external drive, and be able to apply them to another drive. As long as my Mac can store a log of all the changes so far by date, there should be a complete sync. And if I can define a "sync set" of drives, it can use that information to automatically cull the log to not support more history than the least up to date drive. (I could easily spare a terabyte of local storage for such updates, though obviously, there's a limit here - I'd need to clone the drives together initially or when I wanted to add something huge to them.)

Any thoughts?

 

[Saturn007]

My approach to a related use case several years back was to swap external drives. I'd make a second backup at home and take it into and store it at work. Every month or so, I'd make another backup and swap it with the one at work. That let me have a semblance of off site storage. Ongoing projects, I’d back up to an online service from my ISP. Now, I use iCloud for that.

Wouldn't you have to have your backup work drive on line 24-7 so you could connect and backup your drive at home? Not sure how secure that would be…

I've read about online backup services (encrypted and supposedly secure) that will copy your entire hard drive and are accessible from wherever you are. That way, you could access files at work or at home. It probably takes hours to retrieve an entire drive, but I'd assume you could retrieve the full backup to a drive at work or at home.

Why not use iCloud for key documents? You could readily retrieve them as needed from wherever you are. If you made changes at work, they'd be synced to iCloud and available when you got home.