3 Key AS/400 Performance Indicators

One of the nice features of the AS/400 and iSeries platform is it's reliability and administrative requirements. But even in light of this as a system administrator you should also be looking and monitoring key data elements to create a baseline of performance metrics. This data can then be used to gauge system capacity and sizing needs for the future. The critical areas we will focus on are disk space, job monitoring and memory utilization using the tools you already have on your system.

First you will want to tackle any disk storage issues. The easiest way to clear out disk space is to find what objects are using up all the disk space to begin with. This is very simply to do using the Display Object Description command DSPOBJD. Simply do a DSPOBJD for all objects and all object types in all libraries. One of the options is the output type, simple set that to dump the results into an outfile. This file contains all of the object names along with the size of the objects.

After running the command to display all object descriptions, which I recommend running in batch, is simply whip up a quick and dirty Query/400 query or run an SQL statement over the outfile you created. Sort this query by the object size field ODOBSZ and you now can see what objects are taking up all the DASD space.

The one catch I don't like about this technique though is it does not display objects sized once they surpass a certain size, requiring you to add together a couple of fields to get the actual size.

Next up on the list of system performance items is to monitor the jobs using the Work with Active Jobs command WRKACTJOB. This will give you an instantaneous snap shot of all the jobs running on the system along with important pieces of information like how much processor time and storage it has consumed.

For a more in depth analysis of job activity and performance tuning be sure to check out the features built into the iSeries Navigator tool or as I refer to it as Ops Nav. You can do very detailed and in depth analysis on jobs utilizing the underlying DB2 database including graphical tools to show query and SQL breakdowns. With Ops Nav you can also create nice little charts and graphs of key system metrics that are sure to make your manager happy.

Finally be sure to examine how the memory resources are allocated into the system memory pools. To take a look at the current usage of the memory pools check the Display System Status command DSPSYSSTS.

Display System Status shows all of the current memory allocated for the machine, base, spool and interactive pools. There are also other values to help determine memory problems like a running tab of faults and waits. And if need be you can adjust the system memory pools manually by using the Work with System Status command WRKSYSSTS.

However it is usually recommended to allow the AS/400 operating system to tune the memory performance of the system pools automatically by settings the performance adjustment system value QPFRADJ to adjust at IPL and automatically at regular intervals.

John Andersen is an IT manager living in California. Be sure to check out his Midrange Jump Start web site for insider advice and tips on how to manage your AS/400 and iSeries systems.
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