Scaling DB2 Connect memory

In these tests, the DB2 Connect™ z/VM® guest used two virtual CPUs and 512 MB, 1 GB, and 2 GB of memory, depending on the run. The number of user threads was held constant at 500. The IRWW workload driver's think time value was varied from 2000 milliseconds to 5000 milliseconds to vary the workload. The z/VM LPAR was assigned six CPUs and the z/OS® LPAR was assigned four CPUs. The parameter, MAXAGENTS, was set high enough that the number of active connections was not limited.

Figure 1 shows throughput for scaling memory in a DB2 Connect z/VM guest from 512 MB to 2 GB and scaling think times from 2000 to 5000 milliseconds.

Observations

At a think time of 2000 milliseconds there is a slight throughput advantage for 512 MBs. At higher think times there is little throughput difference between the various memory sizes.

Conclusion

DB2 Connect memory size does not affect IRWW throughput in these scenarios. A memory size of 1 GB was selected for the remainder of the IRWW test cases.