Spreading the WORK load

I found a handy tip from Rafi in the discussion Allocating SAS WORK Libraries Dynamically in SAS 9.2 in the LinkedIn group SAS Architects/Administrators/Implementation Specialist. It explains how to use a variation on the SAS system option WORK= to spread work libraries over a number of I/O paths using either random or available space methods. This can potentially help you improve I/O performance for work libraries en-masse, and/or get access to more available space, by spreading those work libraries over a number of different devices.

This usage of the WORK= SAS system option is documented in a number of places:

Resources for Designing and Configuring I/O Subsystems for SAS® Software

As a SAS platform administrator, I often find myself discussing the importance of well designed I/O subsystems with customers and I.T administrators/architects. Sometimes it can be a challenge explaining how important it is for SAS applications to have a high sustained sequential I/O throughput. In some cases they may not consider I/O requirements for SAS software as any different to other applications they are running. In other cases, with the knowledge that it is enterprise software, they may make the well intended assumption to treat it like databases they have experience of and aim for high numbers of small transactional random I/O’s per second. It can be unfortunate when I/O storage decisions and purchases happen before a consultant with SAS software experience gets involved. The purpose of this post is to provide links to a number of resources that can help you make your case for a well designed and configured I/O subsystem for your SAS software installation. I like to provide references to papers by SAS Institute employees because of the value that vendor statements have in reinforcing what I am saying.

These are the papers from SAS Institute that I refer to most often when talking about I/O. They contain very useful information you can use when putting forward your case for high performance I/O subsystems in hardware purchases. If your I.T. administrators are up to a little extra reading it can also provide them with some of the insight they might need when choosing and tuning hardware suitable for use with SAS software. I think the “How to Maintain Happy SAS® Users” paper is a great read for both SAS administrators and the I.T. administrators who work with them.

How to Maintain Happy SAS® Users
Margaret Crevar, SAS Institute Inc., Cary, NC
SAS Global Forum 2009 Paper 310-2009
PDF available from http://support.sas.com/resources/papers/proceedings09/310-2009.pdf
Frequently Asked Questions Regarding Storage Configurations
Margaret Crevar & Tony Brown, SAS Institute Inc.
PDF available from http://support.sas.com/resources/papers/proceedings10/FAQforStorageConfiguration.pdf
Best Practices for Configuring your IO Subsystem for SAS®9 Applications
Margaret A. Crevar, Tony Brown & Leigh A. Ihnen, SAS Institute Inc.
SAS Global Forum 2007
PDF available from http://support.sas.com/rnd/papers/sgf07/sgf2007-iosubsystem.pdf
Improving SAS® I/O Throughput by Avoiding the Operating System File Cache
Leigh Ihnen & Mike Jones, SAS Institute Inc., Cary, NC
SAS Global Forum Paper 327-2009
PDF available from http://support.sas.com/resources/papers/proceedings09/327-2009.pdf

If you would like to add to this list any other papers or resources you know of, that help explain the I/O characteristics of SAS software and appropriate I/O architecture guidelines/recommendations, then please let me know.

Updated 15Sep2010: added Frequently Asked Questions Regarding Storage Configurations to the list of papers.
Updated 04Dec2010: thanks to June’s comment, updated link to more recent version of the How to Maintain Happy SAS® Users paper.