Why run Exchange Server 2007 on Windows Server 2008 vs Windows Server 2003?

I seem to be getting this question a lot from schools as to what is the value of running Exchange 2007 on Windows Server 2008.

I have compiled a list from sources and I also have added my own personal thoughts:

Higher reliability

With self healing NTFS and other reliability enhancements in Windows Server 2008, it just makes sense to put your mission critical email system on this server OS to increase your Exchange 2007 uptime.

Multi-subnet clustering and other clustering enhancements

If you want to deploy a Exchange 2007 CCR cluster that is split across the WAN then you either need to stretch your VLAN across the WAN with Windows Server 2003 clustering (single subnet support only) or leverage the new multi-subnet support in Windows Server 2008 clustering. There are also additional clustering enhancements that make it easier to set up a majority node set, better cluster error logging, etc.

Networking improvements

Windows Server 2008 introduces SMBv2 which in some cases has been reported to increase copy performance by up to 50% across the LAN/WAN.  If you plan on leveraging either CCR or SCR which essentially copies transaction logs across the network from an active to a passive or standby server it would make complete sense to leverage this increased network performance.

Additionally, it supports an increased number of RPC connections which means you can really scale some of your heavier RPC client users such as your Outlook Anywhere population.

Finally, if you plan on going to IPv6 your Exchange servers would be ready to support this from a server OS perspective down the road.

IIS 7.0 improvements

If you plan on using a CAS server for OWA, Outlook Anywhere or ActiveSync it would just make sense to use a higher performing web server for this. I don't have the raw performance data but I can tell you that in the past, the IIS versions have typically increased in performance by around 20-30% for each version.  I certainly can notice my OWA server render and respond quicker running on IIS 7.0. With the addition of output caching and other performance enhancements it would make sense to leverage these new features.

Additionally, IIS 7.0 provides a greater level of security with its modular approach to only install what is needed which provides a reduced attack surface. If you are publishing your CAS server to the Internet again you would want to do so with the most secure approach.

Finally, IIS 7.0 provides a better administrative experience via easier GUI, powershell scripts, better troubleshooting with tools such as request tracing, etc.

Easier deployments

Since all the default components for Exchange 2007 are installed on Windows Server 2008 it provides you a faster deployment. Additionally, installation of Windows Server 2008 even manually has been greatly improved so you don't have to wait around to click next, etc. 

If you couple Windows Server 2008 with the newer automated deployment technologies such as Windows Deployment Services you can quickly deploy Exchange and the OS unattended if you want via F12 network boot for example.

You don't have to worry about upgrading at a later point. You are set.

The final reason to deploy Exchange 2007 on Windows Server 2008 is you don't have to worry about extended support agreements, etc when mainstream support ends for Windows Server 2003 in July of 2010. You are current.

Conclusion

I hope this provides you some insight into deploying Exchange 2007 on Windows Server 2008 now vs waiting. For more information on Windows Server 2008 features click here.