Tag Archives: Disk Cache

A Summer Project

One of my summer projects is building and performance tuning a relatively inexpensive analytics server. Many of the parts that are being used have been scavenged from another server or two that have been retired. One thing I want to do this summer is report on what I have discovered in performance tuning a modest server.

The server consist of a six core AMD processor and 16GB of RAM to start out with. I would like to experiment with different combinations of RAM, hard drives, hard disk controller cards and perhaps an SSD or two. The OS will be Linux, Ubuntu 14.04 specifically.

My baseline build has just two work drives in RAID-0 and use the SATA 3 ports on the motherboard. I will use the Workstation Performance Assessment Program that I wrote about back in 2012. I’ve slightly modified that program so that it doesn’t spew output in the listing with the exception of the actual performance benchmark.

One thing I have already learned is that you need to make sure that you have the Write Cache enabled. In Ubuntu, you would do this by going to Disks and clicking on the options button at the top right of the dialog box and then selecting Drive Settings. Simply select the Write Cache and click on Enable Write Cache. You will need to do this for each disk in the raid array.

ubuntu_disk_cache

When I enable the write cache, my timings for the PROCs and data steps that took place on data sets that existed on the work array dropped 35%. That’s a big improvement!

About the author: Phil Rack is President of MineQuest Business Analytics, LLC located in Grand Rapids, Michigan. Phil has been a SAS language developer for more than 25 years. MineQuest provides WPS and SAS consulting and contract programming services and is a authorized reseller of WPS in North America.