What Happened to the IBM i PCRM?

The Performance Capabilities Reference Manual (PCRM) was THE resource many used when they needed to know something about IBM i performance. That something could be information about performance test results, I/O performance information, performance considerations for IPL, save/restore, partitioning, CPW ratings and many other miscellaneous topics. The last large version of the PCRM was published for IBM i 7.1 in August of 2013. When IBM i 7.2 became available in spring of 2014, that update of the PCRM was substantially smaller.

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IBM i Selfie

In the IBM i Performance Analysis Workshop, we reinforce the concept that many forces outside of system software or applications can influence the performance of your partition. These are typically configuration type details—anything from how you have the QPFRADJ (Performance Adjuster) system value set, to the amount of memory on your partition, to how you have your processors configured.

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New Monitor Metrics in 7.2

Some time ago, I wrote about the Navigator monitors that were added in the IBM i 7.2 release. The system monitor metrics are performance measurements of different aspects of overall system performance and the data for all these metrics comes from Collection Services. In that blog, I briefly mentioned some of the new monitor metrics that were added – temporary storage utilization, spooled file creation rate, shared processor pool utilization and others. This week I will expand a bit upon the new monitor metrics.

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IBM i Disk Watcher Can Do More

As you probably know, you can use Disk Watcher to collect disk performance data and use it to diagnose disk related performance problems. Typically, Disk Watcher is used for analysis focused on a particular disk unit or auxiliary storage pool (ASP) that’s having performance problems. However, this is not all Disk Watcher can do. It also has the capability to obtain data about all I/O operations being performed on the system, along with which threads or tasks are issuing the I/O operations and which objects or files are being accessed by those I/O operations. This information can be used to help understand which jobs are accessing which objects and how many I/O operations those jobs are performing on each object. 

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