PI System clients and high availability

Clients are the component of the PI System used to access and view data on Data Archive and features such as tag search, performance equations, etc. Implementing high availability for client connections allow you to mitigate and minimize the effects of a disruption to the client in the event that the Data Archive server goes down.

High availability is implemented for Data Archive through a Data Archive collective. A Data Archive collective is a configuration of multiple servers that act as a logical Data Archive server in your PI System to provide high availability, disaster recovery, load distribution, increased scalability, and connection balancing. Each server in a collective is called a member of the collective.

To implement high availability between the client and Data Archive, you must first configure multiple Data Archive servers into a collective. Then, configure the client to connect to any Data Archive server in that collective and seamlessly switch to another server within the collective in the event of a failure or disruption of the primary server.

There are different types of client connections available to the Data Archive server, including:

• AF SDK

  Microsoft .NET assembly that provides access to objects and features of PI Asset Framework. PI AF SDK is available for both 32-bit and 64-bit Windows operating systems. Some AF SDK clients include PI System Explorer and PI Vision.

  Note: This client connection requires PI AF Client 2018 or later.

• PI SDK

  The COM-based software development kit for PI System applications. PI SDK is a set of programming libraries for development of Microsoft Windows client programs or interfaces that can communicate with most PI Data Archive versions (PI Server 3.2.357 and up) on any supported operating system.

You may also want to implement N-way buffering for PI clients to protect against data loss if Data Archive becomes unavailable.