HP OpenView System Administration Handbook [Electronic resources] : Network Node Manager, Customer Views, Service Information Portal, HP OpenView Operations نسخه متنی

Figure 8-1. Select

OptionsData Collections & Thresholds from the menu bar to configure SNMP data collection.

Figure 8-2. Add a new data collection by selecting

EditAddMIB Objects… from the

Data Collection & Thresholds dialog box.

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Figure 8-3. Traverse the MIB tree and select the MIB variable for the collection. The collection defined in this example is

ieee8023MacTransmitted , which indicates the number of frames successfully transmitted.

Figure 8-4. When configuring a collection, define the

Collection Mode , the

Source , and the

Polling Interval for the data collection. Type the hostname for the

Source and click

[Add] .

Chapter 9, "Scalability and Distribution."

Setting a polling interval of five seconds (5s) allows you to capture data quickly and verify that the collection is functioning properly. When the collection is functioning to your satisfaction, modify the polling interval to a more reasonable value, such as 30 minutes (30m) or 1 hour (1h). Polling too frequently takes additional bandwidth, CPU resources, and data storage space.

Additional fields available from the data collection dialog may be also customized. If a device contains multiple instances of an item such as file systems or network interfaces,

Instances allows you to specify whether to collect on all or some of the instances. For example, if you have multiple network interfaces but only want to specify a collection for interface one and four, you would specify as the instance From List

1,4 .

You may want to limit a collection by nodes with a specific OID (for example, to limit to a specific vendor's equipment) by selecting the option. This works well when combined with specifying a group of IP addresses (158.153.*.1):

Only Collect On Sources With sysObjectIDs .

By default, traps are not generated when the SNMP query fails. This may be enabled by selecting

Create Event When

SNMP

Request Fails .

Field-specific help is available from this and many other dialog boxes. Selecting a field and pressing the F1 key accesses field-specific help. Detailed information may be obtained from any dialog box.

5. Select

   FileSave to save the collection. Select the newly defined collection and select the menu item

   ActionsResume Collection and then

   FileSave .

6. Wait a minimum of two polling intervals (10 seconds, in this case) and select

   ActionsShow Data as shown in Figures 8-5 and 8-6.

   Figure 8-5. To view the collected data, select the collection and select

   ActionsShow Data… from the

   Data Collections & Thresholds dialog box.

   
   

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   Figure 8-6. The data is displayed as it is collected. Note the five interfaces shown in the upper section of the dialog box. The data being displayed corresponds to the selected interface. Click the

   [Graph] button to graph the collected data.

   
   

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Figure 8-6 displays the data as it is being collected. Collected data is stored in the directory

$OV_DB/snmpCollect . This directory should be monitored as the data collection files can grow without bound. You may want to set up a batch program to periodically archive and remove the data in this directory, or you can delete it as you export it to the Data Warehouse.

NNM provides a command-line utility

snmpColDump to display the collected data in ASCII format. For each MIB variable instance collected, NNM creates two files: a binary file containing the data and an ID file containing information about the variable. The data file is named the

variable.instance and the ID file is the same followed by an exclamation mark (!). To list the collected data for the fourth interface in ASCII format, type the following:

1. Set the current directory to the data collection directory.

   cd $OV_DB/snmpCollect

2. List the collected data for interface number 4 for the MIB variable ieee3023MacTransmitted.

   snmpColDump ieee8023MacTransmitted.4 | more

8.1.2 Defining an MIB Expression for Collection

A MIB expression may be used to define a collection. If no single MIB variable exists for the data you are interested in, you can define a formula using a combination of MIB variables. For example, if you are interested in the percent of available bandwidth utilized on an interface, this can be calculated using a combination of the variables received byte rate, transmitted byte rate, and interface link speed. The pre-defined MIB expression

If%util defines the MIB expression for available bandwidth.

To display the MIB expression

If%util and description, open the

Data Collection and Thresholds dialog box. Select the

If%util collection and select

EditModifyMIB Objects from the menu bar. Then click the

[Describe] button. Expression calculations are in Reverse Polish Notation and can be a combination of variables and numbers. Figure 8-7 shows the calculation and description defined by the

If%util MIB expression. You may select these expressions to add to the list available for configuring specific collections.

Now that you have collected data, you are ready to begin analyzing the information collected. During analysis, consider what values appear to be in a normal state verses an abnormal state. In doing this, you begin to define threshold and rearm values for your data.