Troubleshoot Historian Performance

There are many parameters that affect Historian Server performance and scalability. This topic emphasizes the parameters that help improve performance and scalability.

Buffer Memory Max

Buffer Memory Max allows you to specify the maximum memory buffer size that an archiver queue can take. Use this parameter to control memory allocation to the write queues. If you plan to collect large amounts of data with high update rates, increase the Buffer Memory Max size. Increasing the Buffer Memory Max size provides enough memory for write queues, thus increasing the Historian performance. Refer to The Global Options Section for more information.

Performance Counters

Historian provides a variety of performance counters that can be used to monitor how well the application is performing. Using the following performance counters you can determine the Historian Server performance and scalability:
  • Perftag_GenericWriteQueueSize: displays the total number of messages present in the Generic Write queue.
  • Perftag_FastReadQueueSize: displays the total number of messages present in the Fast Read queue.
  • Perftag_CollectorDataWriteQueueSize: displays the total number of messages present in the Collector Data Write queue.
  • Perftag_EventMonitorQueueSize: displays the total number of events present in the Event Monitor queue.
  • Perftag_DataWriteQueueSize: displays the total number of messages present in the Data Write queue
  • Perftag_ReadQueueSize: displays the total number of messages present in the Read queue
By monitoring the above performance counters, make sure that you manage application performance. Ideally, all write queues should be zero for optimum archiver performance. If you see an increase in back logs in write queues, then you can:
  • Control archive transitions by having larger archive file size.
  • Control update rate.
  • Perform a backup when an archiver is in stable state.
  • Control the caching evaluation period. Refer to Historian Performance Counters for more information.

System File Cache Tuning

Historian allows you to specify the maximum disk cache memory that an archiver can use. Ideally, Historian consumes 25% of system memory. If your computer has extra memory, then you can increase the disk cache memory to optimize Historian performance.
Note: You should not increase disk cache memory if you do not have the necessary system resources.