We've discussed OMEGAMON CICS and DB2 DASD collections considerations. Now let's take a look at OMEGAMON z/OS. OMEGAMON z/OS collects it's device and performance information, such as MSR times, from it's API to RMF. RMF collects the device level statistics, and OMEGAMON displays and analyzes it. DASD information in OMEGAMON z/OS may be seen in both the 3270 (classic and CUA) and in the Tivoli Portal GUI interface.
Recently I was asked by a customer about a message that started showing up on their Tivoli Portal event console. Here is an example of what they were seeing, a situation called "KM5_No_SYSPLEX_DASD_FILTER_WARN". What this situation highlighted was that monitoring DASD devices without a filter that eliminates some of the devices can lead to potential high CPU or storage problems within the monitoring infrastructure. The situation notifies the user that OMEGAMON z/OS does not collect shared DASD device data unless a DASD filter situation has been created, and is active.
So the next question may be, how do you enable the DASD filter situation? The procedure is pretty well documented in the OMEGAMON z/OS User Guide. Here is a link to the appropriate documentation pages:
The Users Guide also has some good recommedations on situation settings, such as collection intervals. I suggest you take the time to review theses options. Keep in mind that the more data you collect, and the more frequently you collect it, the more potential monitoring overhead.
I will talk more about OMEGAMON z/OS DASD monitoring in a subsequent post.