Last week I was running load tests in between other tasks on my agenda. As stated in previous post I wanted to compare performance, as measured by load testing tools, on an old SAN and a new one, EVA and 3PAR respectively. I ran two types of tests, the OLTP test and the SIMPLE test:
orion -run oltp -num_disks 50
orion -run simple -num_disks 50
Following are charts from the ORION OLTP test with “num_disks” equal to 50.
Test was running against one disk (LUN) pr execution. Only test-server has been migrated to 3PAR and ORION were run before and after. Not surprisingly the 3PAR can achieve higher number of I/Os per second as the load increases. The EVA seems to behave erratic or breaking down after some point. This is confirmed in the following chart for latency:
The wild values from one of the EVA-tests throws the chart out of proportions. But it is still possible to see that the latency is within reasonable limits. By limiting the values from 0 to 50,000 microseconds the chart looks like:
Looks like I could have expanded the range when testing the 3PAR. Latency is within 10-32 ms the whole range. Latency is the most important measure for databases IMHO, and after testing this repeatedly on 3PAR I expect to have more stable performance after migration.
Next chart is a histogram for the latency values:
The main difference between them is the outliers on the right side for the old EVA.
The following charts are from the SIMPLE test. In this test the pattern is less erratic for EVA, but still the 3PAR performs much better and seems to be very happy as the load increases.
The SIMPLE test measures throughput with MBPS. Here large I/Os are used to simulate a situation where throughput is more of a concern. The pattern resembles that of the previous picture, and the throughput of the 3PAR is amazingly stable. I’m wondering if it will be just as stable when we move production next week.
The last chart shows the latency of the SIMPLE test, small I/Os where used:
In summary: The ORION tests indicates that the 3PAR is much more stable, and by looking at the results for latency more fit for serving a database server than the EVA. The pattern on the EVA was similar on both production and testing servers, which means that the extra load from other users in production did not explain the oscillations.
Next post on Hammerora will show a similar pattern. I learned a lot by reading the documentation of Hammerora. It is very educational by giving good advices on how to plan and run tests. I felt my ORION testing was a bit inferior compared to the rounds with Hammerora after I finished them, but I still think the results from ORION are interesting. More on that in a few days.