I was recently working with a client who wanted to develop Workflows using VS 2008 on a 64 bit server. After quite a bit of research we found that this was not possible by design. Possible workarounds involve adding a 32 bit server in a 64 bit farm. To check the possibility of this option I researched to find any known issues.
After reseraching I found there was no consolidated article but scattered information across MSDN articles. So thought of blogging on this.
You can deploy an Office SharePoint Server 2007 farm on a mix of 32-bit and 64-bit servers, provided that you maintain architecture homogeneity at each topology layer. For example, you should not mix 32-bit and 64-bit Web front-end (WFE) servers, but you may use 64-bit database servers in a farm with 32-bit WFE servers and application servers. There are some supported scenarios, which allow having a mix of 32 bit server in a 64 bit farm:
1. You may have a DB Server with a different bit value (32 bit) in a 64 bit farm or vice a versa
2. You may have Application servers (in this order) with a different bit value (32 bit) in a 64 bit farm or vice a versa
3. WFE servers – Provided all WFE servers have the same bit
The reasons for avoiding a mix at the same topology layer are:
1. Performance issues
2. Maintenance Overhead - In mixed 32-bit and 64-bit scenarios, it is necessary to manage things such as third-party applications, custom solutions, software patches, and updates independently for each platform.
About performance and capacity planning (Office SharePoint Server)
Advantages of 64-bit hardware and software (Windows SharePoint Services 3.0)