Earlier this year, Microsoft confirmed that it would now support OCS 2007 in a virtualised environment. This has been a big ask by clients pretty much ever since OCS was launched. Just about every time I’ve taught OCS in the past couple of years, as well as in the OCS newsgroups, the question of why it’s not supported comes up over and over again. Along with anecdotal evidence that it worked in at least a VMware ESX environment. And in the classroom, we see OCS working (well as least the server components) just fine.
The support Microsoft is providing caters for OCS server roles running in VMs hosted on both a single server (a typical classroom scenario) or hosted on a number of servers (a scenario more likely in corporate deployment). Support is limited to a subset of OCS Server roles, i.e. Front-End Servers, Back-End SQL Server 2008 (64-bit), Group Chat Channel Servers, Group Chat Channel and Compliance Servers, and Access Edge Servers. This means no support of other server roles - Microsoft say these roles are not supported due to “possible quality issues” with real time media.
It took MS a while after R2 was released to support this - I understand that part of the delay in announcing full support was testing. MS always wants (needs!) to test anything it offers to support, and OCS is no different. In announcing VM support, MS has tested a fully distributed topology with 40,000 users and 10,000 group chat users. This means, says Microsoft that: “audio/video/web conferencing servers, audio/video/web edge conferencing servers, dial-in conferencing, Communicator Web Access, enterprise voice, or Remote Call Control may not be deployed as part of the virtualized pool.” The impact of this means that you can not (at least in a supported fashion) virtualise a Standard Edition pool (or for that matter an EE consolidated pool), a consolidated edge server or a CWA server.
Microsoft also published an interesting whitepaper detailing the tested architecture. The white paper also looks at OCS performance and how you can use the Capacity Planning Tool.
This is a great move forward but it comes with some strings. Namely, the roles that are supported only work in an administratively complex environment. Or to put it another way, all the easy installations of OCS (SE, consolidated EE pool, consolidated edge) can not be virtualised in a supported way. And since, with R2, Microsoft has de-emphasised the distributed architecture, to deploy OCS in a virtualised environment, you would need to use the command line tools which makes the deployment potentially more work. I am hoping we’ll see a better story with the next wave of product.