The web role’s responsibility in a SharePoint farm is to respond to user requests for pages. This involves fetching content from the SharePoint databases and “look and feel” from the database and file system and then rendering, caching (depending on settings), and returning the page to the user. It is a good candidate for virtualization, as long as SharePoint architects take a few key factors into consideration:
- Do not put all your eggs in one basket! Do not host all your WFE’s on the same physical host. Split these virtual machines over a minimum of two physical host machines. This ensures hardware redundancy. If one physical host fails, the remaining web front end server can take over the load.
- Dedicate virtual network adaptors and virtual switch to internal and external MOSS farm communication. For example, ensure separate virtual network adaptors are provisioned to enable you to dedicate virtual network adapters to transport different types of traffic.
- Consider using hardware load balancing over software load balancing: Hardware load balancing offloads CPU and I/O pressure from the WFE’s to hardware layer thereby improving availability of resources to SharePoint. Examples of Hardware: F5 BIG IP, Citrix Netscaler, Cisco Content Switch. Software load balancing examples are Windows Network load balancing, Round Robin load balancing with DNS. It’s a trade-off between cost and performance.