Scenario
Assume that your site has four computers on the SAN:
Computer 1 is a database application server
Computer 2 is a tape backup server
Computer 3 is a tape backup server
Computer 4 is an "extra" that is not dedicated
Setting Goals
You want to be able to include the database server in EVM jobs so that you can use EVM's Application I/O Handler to replicate databases without taking them offline. You also want to include the tape backup servers so that you can use EVM's Backup Handler to automatically run tape backups.
Analyzing Solutions
From the goals, it is certain that computers 1, 2 and 3 must be EVM enabled, because they will be included in EVM jobs. The EVM Server could be installed on any of these, or on computer 4.
EVM Server Solution A
You perform the EVM Server installation on computer 4. This solution provides some degree of load balancing by placing most of the EVM application on a server that will not be performing other significant tasks. This solution is possible because you do not intend to select computer 4 for any role in an EVM job.
EVM Server Solution B
You perform the EVM Server installation on either computer 1 or 2 or 3. Because the EVM Server installation includes the EVM Client, the selected computer can function as both EVM Server and Client and can be included in EVM jobs.