12.4.3 Data Storage in Central Server and DMS

• Overview

• Managed Objects

• Polled Data, Stats Data, and String Data

• Events and Alarms

Overview

The network data is stored in the Web NMS database for persistence. In the distributed setup where the DMS deployed in a remote site gathers data and sends to the Central Server, it is important that some important data is persisted in DMS database, and is also made available in the Central database.  

The default implementation for transferring data from the DMS to the Central Server is XML over HTTP. The data is prioritized based on the object data type as high and low priority data and transferred to the Central Server. The DMS maintains the data to be sent in XML format in a buffer maintainer and from here, the data is periodically transferred to the Central Server. The high-priority and low-priority data are maintained separately in the buffer.

The data transferred from the Distributed Mediation Server to the Central Server are,

• ManagedObjects  (high-priority)

• PolledData objects (high-priority)  

• Statsdata/Stringdata (low-priority)

• Alerts and Events  (high-priority)

Managed Objects

The DMS discovers the network resources as Managed Objects, and persists the data in the local database. The same data is sent to the Central Server at the configured interval. The reason for storing the Managed Objects in the DMS database is that, these data serve as inputs for the status polling of the network resources.

Polled Data, Stats Data, and String Data

The Polled Data Objects are persisted in the DMS database because these form the basis for data collection. It contains details like the Polled Data, agent to be polled, data to be collected etc. After data collection, the collected data is stored in the DMS database in STATSDATA table if the collected value is LONG, and in STRINGDATA table if the collected value is a STRING. These information serve useful when the READ-ONLY Web Client provided in the DMS is used to view the data in the DMS database at a given time.  This data is also persisted in the Central Server database.

You have an option for not storing  the STATSDATA and STRINGDATA in the DMS. This is configured in the Polling.filters located in <DMS Home>/conf directory, by providing an additional entry in this configuration file follows:

Events and Alarms

Events are generated in the Distributed Mediation Server in the following ways:

• Info events for the discovered objects - Info events are generated when the managed objects are discovered.

• Events generated through status polling- The discovered objects are periodically monitored to determine the objects status and events are generated for the status.

• Events generated from the traps received - The traps received by the DMS are converted into events.

• Events generated based on the thresholds - During data collected, thresholds are applied on the configured parameters and events are fired based on these defined thresholds.

Following are the two ways in which events are transferred to the Central Server from the DMS:
 

1. Events correlated into alarms: The generated events are persisted in the DMS database and are then  converted into alarms (you can plug-in your own algorithm for correlating events into alarms ). The alarms are captured using a filter, and the event corresponding to each alert is retrieved and propagated to the Central Server. In such case, the alarms are not persisted in the DMS database. Only the events are maintained. The Central Server DB is therefore persisted with both, events and alarms. The configuration entry in the NmsProcessesBE.conf is as given below:   
   
   
   To send the event corresponding to the alert (default behaviour):
    

2. Events sent directly:  You have an option for not storing even the events in the DMS database. This is configured by setting the required value for ENABLE_ALERTFILTER argument in RemoteProbe process defined in the NmsProcessesBE.conf present in <DMS Home>/conf directory. In this case, the events correlation happen in the Central Server and both, events and alarms, are persisted in the Central Server database and not persisted in the DMS. The configuration entry is as given below:
   
   
   To send all the events (configurable):
    

In the same process, you can set the value of argument SEND_EVENTS_IMMEDIATE as true so that the events are sent immediately to the central server: