Exchange 2007 – 64-bit Impact

Stu asked a very interesting question in response to my last post:

The risk for any new product as you mention is that of the unforeseen critical bugs generally addressed within the first few months after wide scale deployments. For Exchange 2007 I’d be interested in reading your views on what the risks are, if any, in this new release from running on 64bit OS through to the new product architecture.

The move to 64-bit clearly has built into it a set of risks of bugs. The key question is whether they are Exchange 2007 risks, Windows 2003 64-bit risks.

If they are Exchange 2007 risks then they are very new.

If they are Windows 2003 64-bit risks then they have been around for a while.

Windows 2003 64-bit has been running 64-bit applications for some time already; SQL Server 2005 was released in January 2006 for instance. Windows 2003 64-bit has been around since the middle of 2005. So the risks of there being a show-stopper in the critical memory and storage subsystems are likely to be quite. They should have probably been uncovered already. Although, having said that, I would be surprised if the Windows 2003 64-bit systems already deployed support anything like the 130 million existing Exchange population.

It is the interaction of the Jet database with the memory and storage subsystems that have given Exchange the biggest problems in recent times.

So if we can have some level of confidence that the memory and storage subsystems are sound, what about the database itself?

I don’t know, but I suspect that the development team have been in the process of removing code here, rather than adding it in. The Exchange database had to perform all sorts of tricks to operate within the constraints of the 32-bit platform, a limitation that is not longer there. If the code has become simpler then it can probably be relied on even more, but now I sound like I’ve taken the cool-aid.

My perception is that overall the move to 64-bit will make life a lot simpler, it does however have a significant set of risks associated with it.