Anyone know of a way to share a block device like Raid-1 across multiple machines? I want to get two machines to share files to the same group of clients for R/W access and have changes replicated between the two machines, so they'd be effective immediately for the other clients. A month ago, I googled, and found a wiki of a bunch of different systems but they each had some fault. Some could only be written to from one place. The comparison section of the page left me ultimately thinking the only things that did what i wanted were GoogleFS (NOT public) and a couple others that were really expensive.
I don't even so much care that the block device is whats replicated, but trying to replicate a file system on demand like that I'm guessing is not possible for locking reasons. (Two people from different servers could lock the same file in the same place and make changes to it. Has anyone here done anything like this before?