Tony Powell
Storage Administrator

Tony manages CIFS, NFS, and iSCSI storage for a privately held American company that employs over 2,000 people worldwide and has annual revenues of nearly half a billion dollars. One of Tony's primary responsibilities involves ensuring 100% availability for a 2.5TB SAP environment. Originally trained as a software engineer, Tony's previous experience includes working with storage at CSC and Nortel.

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The below article was originally published in the March 2006 edition of the Tech OnTap newsletter. To receive the newsletter monthly and enjoy other great benefits, sign up today.

Author: Network Appliance Engineering

What it is: SIO is a client-side workload generator that works with any target. It generates I/O load and does basic statistics to see how any type of storage performs under certain conditions.

How it works: SIO enables I/O performance testing without having to create large application structures (such as databases). For example, SIO can "approximate" a TPC-C-like workload by specifying a 2 to 1 read-write ratio of 4kb transfer sizes with the appropriate number of threads. A recent "Ask the Sys Admin" column details how to install and run SIO.

What Tony likes about SIO: This tool gives me a much better indication of database performance than just running scripts or doing a DD test in UNIX®. Unlike DD, for example, SIO uses multiple threads and allows for more realistic stress testing. And, since it's a command-line tool, it can be easily scripted.

How Tony uses SIO: I use it quite a bit to tune disks and applications. I first started using SIO about a year ago when we were doing a big SAP migration from HP to AIX. I had written a script that would create and read files, but it wasn't getting good randomization. Using SIO helped me make decisions about how to lay out the file system to get the best performance. Not having to do additional tuning halfway through the migration was a major benefit—although it was originally supposed to take 45 hours, we completed the whole project in about 20 hours.

I also used SIO to test performance running our Oracle® Databases on iSCSI in a UNIX environment. Performance was pretty good, so we ended up putting our database files on NFS using NAS and putting the redo logos and archival on iSCSI.

Caveats
This tool can help eliminate various factors, but no tool can simulate all possible types of conditions.

SIO Download (Includes Full Requirements)
(Password required, customers only.)

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