Summer has been and gone (mostly without any time to blog anything!) and a whole host of changes have been made and new developments arose. Firstly you might notice that we have re-branded ourselves! As I’d mentioned previously, the name “Core Services” hadn’t been ideal so our team put their heads together and looked at similar teams at other universities and businesses. After much deliberation we’re now officially called Infrastructure Solutions. We’ve already given the name a spin out at a Microsoft Tech Day in Manchester (a very enjoyable early look at Hyper-V on Server 2012) and general consensus is that it’s a vast improvement and a better reflection of our work.
I’d previously started a series of posts about some of the systems and services that we support so I thought that would be a good starting point to reboot the blogging. In my last entry I talked about Microsoft Active Directory which forms the backbone for a lot of other services. This time I want to talk a little about the Sun Ray system and how we use Windows Terminal Services. If you trawl the older posts you’ll find a lot of information on the Sun Ray project. For anyone new to the concept, the Sun Ray system is based on a Thin Client model of desktop units (DTU’s) connecting to a Sun Ray server infrastructure which then manages connections to a pool of Windows Terminal Servers. In our original implementation we had our DTU’s connecting to a pool of Windows Server 2003 Terminal Servers, users were distributed to the servers by a 2X load balancer to try and ensure that no single server took too much load. The system worked as advertised but never really had the performance we had hoped for. We tried a variety of things over the years, patches and updates. We added more Terminal Servers with more powerful processors and significant amounts of RAM. Each of these changes made marginal improvements but never made for a “wow” change. That was until we installed our first 2008 box…
One limitation of our Server 2003 infrastructure has always been our dependence on the Novell back end. The Novell client and Zenworks 7 sit on top of Windows and have been increasingly showing their age. With the Active Directory migration we have been phasing out the Novell systems, as such our new installations of Windows 7 have all used pure Active Directory authentication and have generally proven much faster to login. When we looked at an upgrade path for the Terminal Servers the natural course of action was to move them to Windows Server 2008 R2.
We spent a fair bit of time testing 2008 in our department (where we use quite a few Sun Rays on a daily basis) and were pretty impressed with how it ran. As with all of these services you’re never sure how it will behave under real load so the next natural step was to move some departments over and find out! We’d been busy migrating departments over to Active Directory based file shares, as departments moved we also swapped over their Sun Rays. FM were the first department to fully move over to the Server 2008 Terminal Servers and our initial feedback was very positive. Since then we’ve moved almost all of our Sun Ray users, only Faculty of Education and a few areas of Health remain on the 2003 environment. With the file migration approaching its completion we can finally move all remaining users and decommission the 2003 terminal server environment completely.
The hardest part of this change has been balancing the load between two different systems. As I mentioned the 2003 servers used a 2X load balancer, for 2008 we use a session broker to achieve much the same. The hard part is actually reinstalling the servers as we’ve had to remove them from one infrastructure, re-image the servers and then move them into the 2008 system.. all while ensuring we keep enough 2003 servers running for the users who haven’t migrated yet. Generally we’ve done this by taking a 2003 server out on a Friday, re-installing it as 2008 over the weekend and having it all up and running in time so that the migrated users get to login to it on Monday morning. By managing the move so that we transfer around 10-20 users per server moved we can keep both systems running with plenty of capacity.
Hopefully that’s given you a decent overview of the Sun Ray migration, there’s a wealth of information in the old blog posts if you want to know more about the Sun Ray system as a whole. With luck I’ll be able to report back soon to say that the migration is completed and that the good feedback continues!