| f the nice features of the AS/400 and iSeries platform | | | | command WRKACTJOB. This will give you an |
| is it's reliability and administrative requirements. But | | | | instantaneous snap shot of all the jobs running on the |
| even in light of this as a system administrator you | | | | system along with important pieces of information like |
| should also be looking and monitoring key data | | | | how much processor time and storage it has |
| elements to create a baseline of performance metrics. | | | | consumed. |
| This data can then be used to gauge system capacity | | | | For a more in depth analysis of job activity and |
| and sizing needs for the future. The critical areas we | | | | performance tuning be sure to check out the features |
| will focus on are disk space, job monitoring and | | | | built into the iSeries Navigator tool or as I refer to it as |
| memory utilization using the tools you already have on | | | | Ops Nav. You can do very detailed and in depth |
| your system. | | | | analysis on jobs utilizing the underlying DB2 database |
| First you will want to tackle any disk storage issues. | | | | including graphical tools to show query and SQL |
| The easiest way to clear out disk space is to find | | | | breakdowns. With Ops Nav you can also create nice |
| what objects are using up all the disk space to begin | | | | little charts and graphs of key system metrics that are |
| with. This is very simply to do using the Display Object | | | | sure to make your manager happy. |
| Description command DSPOBJD. Simply do a | | | | Finally be sure to examine how the memory resources |
| DSPOBJD for all objects and all object types in all | | | | are allocated into the system memory pools. To take |
| libraries. One of the options is the output type, simple | | | | a look at the current usage of the memory pools |
| set that to dump the results into an outfile. This file | | | | check the Display System Status command |
| contains all of the object names along with the size of | | | | DSPSYSSTS. |
| the objects. | | | | Display System Status shows all of the current |
| After running the command to display all object | | | | memory allocated for the machine, base, spool and |
| descriptions, which I recommend running in batch, is | | | | interactive pools. There are also other values to help |
| simply whip up a quick and dirty Query/400 query or | | | | determine memory problems like a running tab of faults |
| run an SQL statement over the outfile you created. | | | | and waits. And if need be you can adjust the system |
| Sort this query by the object size field ODOBSZ and | | | | memory pools manually by using the Work with |
| you now can see what objects are taking up all the | | | | System Status command WRKSYSSTS. |
| DASD space. | | | | However it is usually recommended to allow the AS |
| The one catch I don't like about this technique though is | | | | 400 operating system to tune the memory |
| it does not display objects sized once they surpass a | | | | performance of the system pools automatically by |
| certain size, requiring you to add together a couple of | | | | settings the performance adjustment system value |
| fields to get the actual size. | | | | QPFRADJ to adjust at IPL and automatically at regular |
| Next up on the list of system performance items is to | | | | intervals. |
| monitor the jobs using the Work with Active Jobs | | | | |