Resource statistics are requested on the basis of resource classes. A resource class can specify that statistics are collected and NTS collects statistics for any resource that matches the resource class, provided that the resource statistics function is not disabled.
NTS collects resource statistics at specified intervals. These intervals can be thought of as discrete buckets into which NTS accumulates all accounting data for a particular resource during that period. When the specified interval expires, NTS resets the counters to zero and starts collecting data in a new bucket. After a specified (or default) number of intervals, NTS wraps, that is, overwrites the counters for the oldest interval, and so on.
Intervals provide one of the basic units for the analysis performed by the NTS Resource Statistics option.
NTS attempts to collect RTM statistics for PUs (specifically, cluster controllers) if both of the following conditions apply:
On the expiry of an interval, NTS solicits RTM data from a resource that meets these requirements, while simultaneously resetting the RTM counters of the resource. In this way, accurate response time data is collected for each interval.
NTS collects the following sets of RTM statistics:
If no RTM responses received from a resource have the exact format specified in the matching RTM class, aggregate RTM statistics are collected only.
If one resource involved in a session is defined in a remote domain, NTS can still collect statistics for the cross-domain resource, provided the following conditions apply:
When an ISR link is established, a handshake occurs that lets each NTS calculate the time difference between the system clocks. This figure is then used to calculate the completion time of the resource statistics collection interval of the other NTS. The remote NTS waits until this time before forwarding the collected statistics to the local NTS.
If no suitably-configured ISR link exists or if resource statistics collection is disabled in either NTS, no cross-domain statistics collection occurs.
If NTS has been instructed to collect statistics for a particular resource, it automatically uses SAW data to monitor the availability of that resource. A resource is considered available if it is participating in a session with the SSCP of the domain in which it is defined.
When NTS is notified by VTAM of the first session involving a resource, an SMF record is presented to the NTS User Exit, indicating that the resource is available. When notified of the termination of the last session in which the resource was involved (that is, the session with the SSCP), NTS presents an SMF record to the NTS User Exit indicating that the resource is unavailable. In addition, SMF records containing interval-based resource statistics are presented to the NTS User Exit, indicating what the current status of the resource is.
When the resource statistics collection interval expires, NTS waits for a period of up to the correlation interval for any outstanding statistics. These statistics may consist of the following:
NTS reports the arrival or non-arrival of statistics from other domains in the activity log. In the case of the non-arrival of statistics, the log entry specifies why statistics were not received from other domains. A separate log entry is created for each SSCP of which NTS is aware.
When this process is complete, NTS writes an entry to the activity log signaling that logging is about to commence. In this way, you can gain an accurate indication of the completeness of the statistics collected for each resource statistics collection interval.
Finally, NTS passes all the statistics collected during the interval to the NTS user exit, if one is active.
Note: Resource statistics are not logged to the NTS database, but passed to SMF for processing.