We have ~ 10 desktop PCs on our company LAN, all with Windows 7 (but a mix of 32bit and 64bit editions). Every single one of those desktops has between 50GB and 400GB of totally wasted disk space: they come with big disks and are used for a little more than the usual explorer/outlook/excel workload. Some quick check shows a minimum of 1.5TB of raw storage on 10 different desktops on gigabit ethernet LAN that could be taken off the users without impacting them. The PCs can come and go from the network (being turned on and off) but are online for the most part of the working day.
We also have a linux server that is online 24/7/365. I wonder if I can harvest in any way the unused disk space of the desktops, eg. to run some distributed and replicated storage on them and possibly access it from the linux server.
I imagine something that would be useable when a minimum number desktops are online (quorum style) and that will automagically update other systems when they come online at a later time. Ideally it should be accessible from the linux server, but it does not need to be a mountable filesystem, or a filesystem-like thing at all. Anything goes, like an object store accessed via REST queries or whatnot.
The only single big essential requirement is that it must not impact the user experience on the desktop: we can install and setup stuff on those PCs but it must not require user interaction during day to day operations, and the user must be free to turn off its PC whenever he wants without getting stuff like "there are $foo users connected, should I terminate them?"
What usage would that be for is out of the scope of this question, it's more of a technical exercise than a production deployment.
Is there some software component I could install on the Windows-7 desktops get something like what I described?