NFM-P statistics scalability

Overview

The overall volume of collected statistics is limited by the available storage resources. Therefore, the number of objects and collection frequency must be specified to meet operational requirements and remain within the storage constraints.

When a statistics collection policy or an accounting policy applies to a large number of objects, the collection interval must be sufficient to collect all of the data during the collection period. If the statistics collection time exceeds the collection interval, the NFM-P raises an alarm.

The maximum number of statistics the NFM-P can collect is specified in the NSP Planning Guide. To prevent statistics loss and NFM-P performance degradation, it is recommended that you stay within the specified maximum guidelines and ensure that each collection interval is sufficient for the number of statistics to be collected during the interval.

You can use NFM-P auxiliary servers to reduce the statistics collection load on a main server. Auxiliary server deployment is supported only in a distributed NFM-P system. See the NSP Planning Guide and NSP System Architecture Guide for information about auxiliary servers.

Real-time statistics collection and graphical display are supported for many network and service objects. An NFM-P client can open up to five real-time plotter windows, and each window can display up to eight counters. If multiple open statistics plotters point to the same NE or the same object on an NE, the NE receives a large number of SNMP requests. It is recommended that you limit the number of open statistics plotters for the same NE. You can use a span of control to limit operator access to specific NEs and thereby reduce the number of simultaneous real-time collections from a specific NE.

Note: The NFM-P limits the number of active MIB-based accounting statistics plots per NE to four among all NFM-P clients. For example, when two NFM-P clients each have two active MIB-based accounting statistics plots associated with the same NE, no other client can open a plot of the same type for the NE.

Accounting statistics

If you need to collect large numbers of accounting statistics, for example, more than one million, it is recommended that you enable the statistics collection in a staggered manner. This helps to prevent the first-time collection delays associated with building the initial cache. For example, if you need to collect 6 million statistics in a 15–min interval, enable 500 000 statistics and wait until the interval completes before you add the next 500 000 statistics, and so on.

You can use custom accounting records to limit the processing requirements of service, subscriber, or AA accounting statistics collection. See Chapter 4, Accounting statistics for information about custom accounting records.

The NFM-P uses FTP or SCP to retrieve an NE statistics file when the NE notifies the NFM-P of the new file. The NFM-P retrieves and processes the files in the order that it receives the notifications. An NE retains files only for the period specified in the file policy; after this period, the NE deletes the files. The statistics data in the files is lost if the files are not retrieved from the NE during this time.

Note: After an extended loss of connectivity to an NE that has an active accounting policy, the NFM-P resumes accounting statistics file retrieval by starting with the most recent statistics file.

When an accounting statistics counter is not supported by an NE or is excluded from collection using a custom record, the counter value is not included in a statistics record or displayed in the NFM-P client GUI.

Performance statistics

When a performance statistics collection interval is too short, statistics data may be lost. Performance statistics that remain to be collected at the end of a collection interval ares skipped, and the next collection begins.