Of late I've been thinking what kind of backup/sync tool would serve the multi-pronged requirements of a power user, having a wishlist looking something like:
Support for multiple directory profiles
Most online sync tools let you sync just one top level folder and all its contents. What if I want to sync multiple folders at distinct locations, with low configuration overhead?
Configurable web storage
There are a handful of distinct kinds of backup/sync paradigms most prevalent these days:
Dropbox-like services which lock you down to using their own online storage infrastructure, with all its incumbent security and privacy concerns.
DejaDup-like software, which let you configure an online storage infra of your choice (S3, ftp, etc.) but are not very flexible in terms of one or more of:
- managing multiple profiles,
- instant updates,
- multi-platform support
Rsync and it GUI derivatives may be counted in this category as well.
Full-fledged VCS like git, svn, cvs, etc. Though powerful and designed from ground-up to support versioning, incremental updates, branching, tagging and much more, they have the disadvantage of introducing metadata into the tracked folders, and are in general an overkill for the simple task of just syncing a bunch of folders. There's also the non-trivial overhead of creating and managing the online repository.
Some services like Dropbox (and VCSs, obviously) provide versioning support, others like DejaDup and rsync don't. I think version control is an invaluable feature to have, especially when tracking important documents. A very basic but life-saving advantage is the ability to restore a previously deleted file.
Most of us are owners of multiple devices, running on multiple platforms. Many of us are saddled with one or more personal/office laptops and desktops, as well as tablets and smartphones. They all run on vastly different platforms. It is incredibly convenient that a document you create on one device becomes transparently available on another, so you can seamlessly switch from your office desktop, where you created that PPT, to your tablet or smartphone at home to add those last-minute finishing touches. Services like Dropbox win hands down on this front, with support for all major desktop OSes as well as mobile platforms.
This is possibly the coolest feature in Dropbox, and was its chief attraction and selling point in amassing the large userbase that it now serves. I know I was impressed by it more than any other feature the service had to offer (other than being free, of course ;)). It's a breeze working with your tracked folder exactly as you would work normally on other folders and let the software take care of syncing transparently in the background. This unburdens us from having to configure scheduled tasks or (god forbid) manually having to push/pull changesets all the time.
Multi-user rw support
Not sure if Dropbox supports this, but VCSs most certainly do, and DejaDup and rsync can be configured to support it with a little effort. For an individual user wanting to manage his own personal files, this is not a critical requirement. The ability to share read-only links to specific files and folders from time to time usually suffices.
Most of the parameters I've listed so far have one or the other clear winner, but it's quite obvious that no single service described here is capable of fulfilling all criteria to adequate satisfaction. To me it indicates there could be an opening for a product/service which meets all the above requirements well enough to satisfy the exacting standards of a power user, while at the same time giving the normal user a handy, one-size-fits-all alternative.