This project involved an underperforming SUN configuration.
When the customer sought a complete system upgrade,
After several days of system monitoring, modeling, and careful analysis, we determined that this installation was data-starved (I/O bound CPU wait averages 66%), but there was sufficient CPU capacity.
We found that the I/O subsystem was constrained and working beyond its rated capacity. We polled the disk controller to study the individual disks and found the following:
The x-axis names the individual disk devices while the y-axis shows the % busy. It is clear that some disk volumes are too busy to meet the requirements of data transfer to the CPU.
When we considered the block characteristics of the disk arrays, we noticed a serious non-linearity.
Upon analysis of this anomaly, we determined that outside consultants had loaded all database and file indices on vol 07.
Our recommendation was to add a new disk array and redefine the placement of files from vol 07 across the new storage system.
Result: Customer saved over $300,000 on an unnecessary system upgrade and still achieved desired performance.