Good day,
I've been out of the country working on a project so I couldn't replay immediately. Thank you for suggestions.
Unfortunately we are stuck with the software and the databases it supports. When we get the trial license I'll try alternative databases because they were my first choice in the matter but we will probably lose support and warranty. Each site will has a PBX so all branch offices will be autonomous in that way. Because the time frame is short vendor can't implement anything. StarWind Virtual San is a good solution for the SQL redundancy and in that way we could cut cost on the SQL licenses and maybe the recording application can be done in the same way. I've been looking at Xen and DRBD but because I've only done that in my lab I'm not confident enough to propose that solution. If we go down the path of virtualization and distributive replicated storage I don't know to make the branch offices SQL servers available if the branch office loses network connectivity or something goes wrong. I guess the databases from each branch office can be replicated or mirrored to the main office and maybe even SQL express license will be sufficient for that. ButI don't have experience with MS SQL replication or mirroring. Also there is one more problem with virtualization because that software requires a PCI express card on each server for redundancy that is used for recording the analog lines. I don't know if it's possible to represent both cards to a single VM where the recording software resides and what drivers are available for it. Of course I'll test every solution in a lab environment and see in what I'm confident enough to do.