SAS CAS Server Architecture

Before you begin to monitor your CAS server, be aware of your CAS server topology, the number of users who interact with CAS, and the volume size of user data. Use the following checklist as a guide:

• Is your CAS server SMP or MPP?The CAS server can run on a single node or as a distributed server on multiple nodes. These two types of architecture have the following distinctions:
  • Massively Parallel Processing (MPP) multi-nodes where three roles are assigned to individual pods for CAS:
    • One controller: When the server starts, the controller process is started. This process is sometimes referred to as the server controller. The controller accepts connections from clients.
    • One or more workers: The CAS server has multiple pods that are assigned to the worker role. The controller parses out work to each worker pod. Each worker pod sends the results of its computations back to the controller.
    • One backup controller (optional): This provides fault tolerance for the CAS controller.
  • Symmetric Multi-processing (SMP) single node where there is only one pod for CAS. The server acts as the controller, and because there are no worker nodes, the controller pod performs the data analysis on the rows of data that are in memory.
• Do you have multiple CAS servers?

export viya=viya_namespace

kubectl -n $viya get casdesployments

• How many users are interacting with the CAS server throughout the day? (How many concurrent sessions during a specified time period?)When resources are provisioned correctly, there can be many concurrent CAS sessions and your CAS server runs without interruption.
• What are the average and maximum sizes of data sets that users load and manipulate?These sizes might affect the amount of disk space that is required for SAS temporary data or the CAS disk cache.
• Which method is used for CAS workload placement on nodes in your cluster?See Workload Placement Strategy.

See Also

• Architecture in SAS Cloud Analytic Services: Fundamentals
• CAS Server Resources in System Requirements for the SAS Viya Platform
• Multiple CAS Servers in SAS Viya Platform: SAS Cloud Analytic Services