Recently I received the question if it's possible to install workflows on separate server. The client wished to have fall back scenario for their CRM application.
You could setup web servers in load balancing setup and if performance issue may occur then it's relatively easy to add another web server, also a fall back server could be stand by.
For Microsoft SQL Server you can use cluster with redundant SAN or NAS solution. These are usually very expensive solutions and very complex to install and to configure. To save costs you could use Dell instead of more expensive HP solutions.
To answer the questions: "Is it possible to install workflow on different server?". No it's not possible only the following roles/service could be installed on different servers (only by using command prompt installation:
- SRS Data Connector
- SQL Server
- Application Server
- Asynchronous Processing Service
- Deployment Service
- Discovery Service
- Help Server
- SDK Server
More details at: blogs.msdn.com/crm/archive/2008/08/20/making-sense-of-server-roles.aspx
Start designing your architecture :-)