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One of the sessions I got a lot out of at the SAS Global Forum was Margaret Crevar’s session where she outlined what options existed for tuning SAS on Windows 2008.
Some recommendations I noted where:
- On Windows 2008 64-bit size: 4Gb of RAM per core. 1.5 x physical RAM for page file
- change default SORTSIZE to equal between 256MB-512MB (removes need for util files if it can be done in memory)
- up BUFSIZE to align with SAN storage stripe size
- undocumented settings UBUFSUZE and IBUFSIZE
- change default SAS MEMSIZE to between 512MB and 2Gb
- recommend between 30 and 50MB I/O throughput per core
- 9.3 metadata recommendations, separate server 4 cores, 4GB RAM – small, 8GB – med, 16GB large, I/O doesn’t really matter
One of the areas Margaret covered was the issues with file cache within Windows 2008. Apparently Microsoft has re-written the file cahce system in Windows 2008 and R1 and then again in Windows 2008 R2. Both of these versions have major problems with SAS environments that have a high I/O footprint. SAS have raised the issue with Microsoft but have yet to have a resolution.
Interesting point was we experienced the same issue in Windows 2003:
Problem Note 36664: Potential issues with heavy SAS® I/O workloads on Windows 2003, 32- or 64-bit operating systems
You can read an excellent paper Margaret has authored at:
370-2011: Configuration and Tuning Guidelines for SAS®9 in Microsoft Windows Server 2008
Some other papers you may want to reference are:
SAS Global Forum 2009 Paper 310-2009
SAS Global Forum 2007
SAS Global Forum Paper 327-2009
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