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What happens when you pair z/OS Connect with IMS?

  

Have you ever wondered how IBM z/OS Connect (z/OS Connect) performs when paired with a blazingly fast IBM IMS? We, the IMS Performance team based out of the IBM Silicon Valley Lab, embarked on a journey to find out just how well it would perform. Read on to see what we observed!

For the full details of the performance evaluation, check out our IBM z/OS Connect Performance Evaluation white paper.

As you might be aware, with z/OS Connect V3.0, not only can existing IMS resources be exposed as RESTful APIs, but you can also call out to external RESTful APIs from z/OS applications running in IMS, CICS or batch. Our goal was to analyze its performance capabilities in both scenarios:

  • API Provider: When IMS resources are exposed as APIs
  • API Consumer or Requester: When IMS applications consume APIs from external hosts

The results of our IBM internal testing, done in a controlled laboratory environment, demonstrated great performance in both provider and requester scenarios.

API Provider Workload Performance:

  • With 1KB I/O messages, throughput peaked at about 21,000 transactions per second before stabilizing
  • With 8KB I/O messages, throughput peaked at about 8,900 transactions per second before stabilizing
  • With 30KB I/O messages, throughput peaked at about 3,500 transactions per second before stabilizing 

The results for this scenario are shown in Figure 1.

Figure 1: API Provider Workload Performance
 
API Requester Workload Performance:

  • With 1KB I/O messages, throughput peaked at about 5,100 transactions per second before stabilizing
  • With 8KB I/O messages, throughput peaked at about 3,800 transactions per second before stabilizing
  • With 30KB I/O messages, throughput peaked at about 2,100 transactions per second before stabilizing 

The results of our testing for this scenario are shown in Figure 2.

Figure 2: API Requester Workload Performance

Because z/OS Connect is a Java based product, approximately 99% of processing is eligible for offloading onto zIIP processors for both scenarios. Results of the potential zIIP offload at different message sizes for the provider scenario are shown in Figure 3.

Figure 3: z/OS Connect zIIP Eligibility

Based on our testing results, z/OS Connect V3.0 paired with IMS 15 delivers excellent performance and scalability for customers interested in exposing existing IMS resources as RESTful APIs or calling out to external RESTful APIs from existing IMS applications.

For more details about the testing configuration and workload, check out our IBM z/OS Connect Performance Evaluation white paper.


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