From time to time we’ll hear from customers who are encountering performance issues. SAS has a sound methodology for resolving these issues and we are always here to keep your SAS system humming. However, many problems can be resolved with some simple suggestions. This blog will discuss different types of performance issues you might encounter, with some suggestions on how to effectively resolve them.
Situation: You are a new SAS customer or are simply running a new SAS application on new hardware
Suggestion: Be sure you’ve read and applied all the guidelines in the various tuning papers that have been written:
- Operating System
- Storage array
- Testing to make sure you are getting 100 MB/second/core IO throughput to each SAS file system
Making sure you understand the performance issues will help us determine what next steps are. It’s worth noting, 90% of performance issues are because your hardware, operating system and/or storage has not been configured based on the tuning guidelines listed above. In a recent case we were able to get a 20% performance gain from a long running ETL process by adjusting two RHEL kernel parameters that have been documented for many years in our tuning paper.
Situation: Your SAS application has been running and over time gets slower
Suggestion: Determine if the number of concurrent SAS sessions/users has increased and/or the volume of data (both input and lookup tables) have increased. This is the top reason for a gradual slowdown.
Situation: Your SAS application took a significant performance hit overnight or in a short time frame.
Suggestion: The first thing you want to do is see if any maintenance (tweaking of your system, hotfix, patch, …) have been made to your operating system, VMware, and/or storage arrays. A lot of customers have applied maintenance (not to SAS) and SAS all of a sudden is running 2-5 times longer. You’ll want to check that all the operating system settings, mount options, and VMware settings are the same after the maintenance as they were before maintenance.
In conclusion, if you are having performance issues, check the suggested tuning guidelines. Also, be sure to keep track of all the settings for the hardware and storage infrastructure when applying maintenance to make sure these settings are the same afterwards as they were before.
Of course, if you have followed the guidelines and maintenance is not the reason for your performance issues, please contact us. We are here to help.