12.4.8 Configuring SNMP Data Collection

Using Mib Manager to get OID and Type

Configuring the Properties for a Polling Object

Overview

Data collection is the process of collecting useful information from network resources such as computers, host resources, switches, routers, etc. The collected data is used to calculate the performance of network and its resources. The performance of your Network depends on the data you select.

You can

specify from which selective resources to collect data
temporarily stop data collection and resume whenever required
set storage options and specify when and where to store data

Polling Object and Polled Data

Polling Object : This object contains two properties:

Match Criteria - Match Criteria denotes the conditions to be satisfied by the Managed Object for the Polling Object creation. Data will be collected for the discovered Object when the specified conditions are satisfied.
Data Collection Criteria - Data Collection Criteria denotes the list of data to be collected from the Managed Object.
Example: isSNMP true. This Match Criterion denotes that the Managed Object must be an SNMP node.

Data Identifier (Polled Data) : This is the unit of data collection, where you can specify the data to be collected and its associated properties. Using this Polled Data, data is collected and stored in the database. Polled Data is also referred to as Statistics.

Example: If the data number of octets received by the interface of a device has to be collected, then a Polled Data with a relevant name can be created. Eg: octets_received.

How It Works

The sequence of steps for configuring data collection are

Polling Objects defined from the Polling Configuration UI contain two definitions, Match criteria and list of Data Identifiers.
The discovered Object is given as input to the Polling Object.
The Polling Object's Match criteria is compared with Managed Object's properties.
If the Match criteria are satisfied, Polled Data is created for every entry specified in Data Identifiers.

Configuring the Properties for a Polling Object

To configure the properties for a Polling Object

Select the Polling Object from the left panel listed under the respective Distributed Mediation Servers.
Select the check box corresponding to Update Managed Objects to update the managed object with the properties of the Polling Object. This will update the properties of the existing managed objects as well as new managed objects. If the check box is not selected, the properties will be updated only for the newly added managed objects.
Select the check box corresponding to Status. By default, this is selected. This implies that data collection is active for the associated polled data. If you clear the check box, data collection for the particular polled data will be stopped.
If there is a common prefix for all the polling objects, you can enter it in the prefix field. This will be appended to the polled data automatically.
Enter the polling period in seconds. Default period is 300 seconds.

Configuring SNMP Data Collection

Let us consider an example of collecting SNMP data for system parameter, say Disk Space. To configure data collection

From the menubar, select Tools --> Runtime Administration -->Performance --> Polling Configuration. The corresponding UI on the right displays a DMS list. The configured Polling Objects for each DMS are displayed under the respective DMSs.
Select the DMS for which you want to add a Polling Object.
Click 'add' button at the bottom of this list. A new Polling Object is added under the selected DMS as Poll Object. You can edit the name of the Poll Object. Eg: Sys_Param.
After providing the name for the Poll Object, click the Add button in the Match Criteria column on the right. A dialog to specify the match criteria pops up
Select the Managed Object Criteria tab (default selection) and click 'add' button in this screen
Specify the match criteria. An example match condition is provided below:

Type - You can select either String or Numeric type from the combo box. Let us select STRING_TYPE for this example.

Property - Specify the managed object property which must satisfy the match criteria. For example, isSNMP.

Test Condition - Select the required test condition that must be satisfied. For example, equals.

Value - Specify the value for the managed object property. For example, true.

Press Enter and click OK. The Polling Object will be added with the specified criteria.
Now, provide the Polled Data in the Data Identifier column. To achieve this, click the 'add' button present at the bottom of the Data Identifier column. A default entry in the name of Data Identifier will be added. You can edit the Data Identifier name as required. For example, Disk_Space.
Enter the values for the Polled Data properties. The oid and type fields are mandatory fields. See the following sub-topic to know how to obtain the oid and type. The type field will take values node, interface, and multiple. If you enter the type as multiple, values will be collected for all the instances and will be stored. If you enter a specific type, like node or interface, value will be collected for that instance alone and will be stored.
Click Apply to effect the configurations.

Note:

When you add or copy/paste a new polling object with an existing data identifier and match criteria, the data identifier object (PolledData object) will not be formed for that Polling Object. You must delete and add new data identifiers. That is, the data identifiers must be unique across all the DMSs.

Using Mib Manager Tool to Get OID and Type

The Mib Manager Tool can be used to get the OID and type of a network resource. Let us consider the example of obtaining the OID and type for Disk Space. Follow the steps given below:

From the tree nodes in the left panel, select the node SNMP Tools-->Mib Manager.
The Mib Manager UI opens on the right panel. In this UI, the left tree displays the MIBs that are loaded. By default, RFC1213-MIB will be loaded.
For host resources, you need to load the HOST-RESOURCES-MIB. To load this MIB, from the File. menu in the MIB Manager UI, select the menu Load MIB.
A Load Mib dialog opens. Using the Browse button, select HOST-RESOURCES-MIB from <Central Home>/mibs directory. Click Open.
The selected Mib will be loaded and is displayed in the tree under the Loaded MibModules.
From this tree, select HOST-RESOURCE-MIB-->mib-2-->host-->hrStorage-->hrStorageTable-->hrStorageEntry-->hrStorageUsed.
The OID for this parameter is displayed at the bottom in the Object ID field. You can provide this value in the oid field in the polling configuration UI for the Polled Data (if the type is multiple).
To get the OID for a particular instance, select the 'get snmp' icon (Get SNMP Variable) from the Mib Manager toolbar. All the instances will be displayed in the right panel of the Mib Manager UI. Append this instance number to the displayed OID value. For example, OID - .1.3.6.1.2.1.25.2.3.1.6
instance name - hrStorageUsed.3
instance number appended - .1.3.6.1.2.1.25.2.3.1.6.3

Note:

To know more on how to provide the OID, refer the section Using MIB Manager.