Advantages to a single PWA instance over multiple PWA instances

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I generally get questions about creating new PWA instances to separate Project Server data, including access to users and resources. The RBS feature (if you are using Project Server permission mode) can be leveraged to control access of Project Server data. Hence, a single PWA instance should suffice for most needs of the organization.

Below are the highlights of some of the benefits of having single PWA instance.

  • A single PWA instance helps to manage resources at the enterprise level. The accurate availability of resources cannot not be measured if the same resource is a part of multiple instances.
  • Every PWA instance has certain timer jobs, which run regularly. If there is more than one PWA instance in the farm, system has to process more timer jobs than it processes with single PWA instance.  
  • Multiple AD and Group Sync processes are required for multiple PWA instances.
  • If OLAP cubes are used, then a cube building process is required for each and every PWA instance.
  • If there is more than one PWA instance in the farm, duplicate efforts are required for taking backup of Project Server databases, Project plans, and other items, such as Eglobal, Security Backup, and Resources backup, etc. Same requirement is applicable for the restore process.
  • SQL Server maintenance is required for all databases of PWA. Multiple instances will have multiple project server databases. Hence, all of them need to be maintained regularly.
  • Test, QA, and/or Development Environment refresh can be time consuming, if there is more than 1 PWA instance.
  • Database migration of the environment to a newer version will take more time for multiple PWA instances vs. a single PWA instance. 
  • More effort is required to maintain multiple PWA instances than maintaining just one PWA instance.

There are a few benefits to having multiple PWA instances.

  • If a single environment would have many thousands of users, hundreds of Custom Fields, many Look Up tables, and thousands of project plans, it may be best broken up into business unit PWA instances.
  • Multiple instances create multiple site collections. Managing site collections which are smaller in size is easier than maintaining a single large site collection. 
  • Different business units may require different Timesheet units, such as Columns and Reporting. A single PWA instance cannot accommodate this requirement.
  • Organizational requirements demand that one or more PWA instances be separated from others. By definition, this means that the resource pools are separate and unaware of each other and also that the resources from one pool are never used in the resource pools of the others.