Creating a user-defined SNMP trap

About user-defined traps

You can create custom SNMP traps to send specific types of information to your management station.

Viewing existing SNMP traps

To view existing user-defined traps, in the Appliance Manager, select Setup tab > Administration > SNMP, then click the Traps tab. Current user-defined traps are listed under the heading Current SNMP Traps. (The heading is displayed as "No Current SNMP Traps" if no traps have been defined.)

Identifying a MIB variable to be used with a new trap

To create a trap, you need to determine the information you want the trap to report on, and then determine the MIB variable that tracks that information. The NetApp MIB lists available variables with short descriptions.

To select a variable and its object identifier (OID) to be used for the trap, you can use the Appliance Manager MIB browser by clicking the Show MIB Browser button on the SNMP page.

You can also obtain the custom MIB from the software CD-ROM or from the NOW Web page at http://now.netapp.com/ (perform a search for MIB). To locate the MIB on the CD-ROM, read the index.htm file in the top-level directory of the CD-ROM.

Obtaining the SNMP object identifier (OID) for a MIB variable

Each variable is associated with an OID. You can obtain the OID from the MIB browser by directly clicking on the OID; this imports it into the OID box on the New SNMP Trap page.

Alternatively, you can obtain the OID from the traps.dat file in the same directory as the MIB after you have determined which variable name you want the new trap to use and create the trap manually.

Parameters for user-defined traps

Use the descriptions in the following table to help you construct entries for trap parameters.

Parameter	Description
Trap Name	Specify the name of the new trap being defined. Valid characters include alphanumeric characters (a through z, A through Z, 0 through 9), the underscore (_), and the hyphen (-). The first character must be alphabetic. Internal spaces are not accepted.
Trap Enable	Enables the trap instance being defined. You do not have to enable the trap at this time. You can define the trap on this page and then enable it later on the Current SNMP Traps option on the Traps tab page.
Variable	Specify the object identifier (OID) for the MIB variable this trap should report on. Use the MIB browser to import the correct OID or enter the OID manually. A list of available variables is located in the NetApp MIB. Example: The OID for the MIB variable sysUPTime is as follows: snmp.1.3.6.1.2.1.1.3.0
Trap ID	Optionally, specifies a trap ID value within the valid range of values reserved for the traps you define. You can use the value 0 (default) or a value within the range 1000 - 1999 inclusive. Specify a short name, or alias, for the trap you are defining. Remaining values in the ID space are reserved for Network Appliance and are not available for your use. If you specify no trap ID or if you specify 0 (the default value), triggering this trap will cause the appliance to issue a specific code based on the priority of this trap. The Trap ID parameter assigns a trap identifier (trap-id) to the information being sent to the management station. This enables the management station to signal alerts to administrators and indicate where the alert originated. Each trap defined in the Network Appliance custom MIB has its own identifier. For each user-defined trap, the management station uses the trap-id associated with the trap's priority.
Trigger	Specify the type of trigger that signals this trap to fire and send information to the management station. When a trap is triggered, data regarding the event that caused the trigger is sent to the network management stations. You can specify the following values: single-edge-trigger--Fires once when the value of the trap's MIB variable meets or crosses the threshold that you specify. You specify the threshold in the Edge-1 field. If the MIB variable value remains equal to the specified value or if it continues to exceed the threshold in the same direction, the single-edge-trigger will not fire again until the value crosses the threshold in the opposite direction and then crosses over again (once again exceeding the threshold specified in the Edge-1 field). The trigger fires each time the variable's value crosses the specified threshold in the specified direction. For a single-edge-trigger, only Edge-1 direction applies. You can set the direction to Up or Down, specifying the crossover direction in which the trigger occurs. double-edge-trigger--Fires when the value of the trap's MIB variable exceeds or drops below a threshold you specify. A double-edge trigger enables you to set two edges, each with its own direction (Up or Down). You specify these threshold values in the Edge-1 and Edge-2 options. For a double-edge-trigger, Edge-1 direction (either Up or Down) specifies the crossover direction that fires the trigger for one edge, and Edge-2 direction (either Up or Down) specifies the crossover direction that fires the trigger for the other edge. (Down is useful, for example, if you monitor for underutilization.) Level-trigger--Fires whenever the trap is evaluated if the value of the trap's MIB meets or exceeds the level that you specify, or remains at the level that you specify after meeting it. Specify the level in the Edge-1 option. Change-trigger--Keeps track of the last value received from the trap. If the current value differs from the previously received value, the trap is triggered. For example, the trap fires when the value changes from 0 to 1. Always-trigger--Instructs a trap to trigger every time the trap is evaluated.
Edge 1 and Edge 2	The Edge 1 and Edge 2 parameters are used in combination with the Trigger parameter values of single-edge trigger and double-edge trigger. Specify the threshold value or values that are compared during trap evaluation to determine whether to fire the trap and send data to the management station. The Edge 1 parameter specifies the value for the edge in a single-edge triggered trap or the first edge in a double-edge triggered trap. The default value for the Edge 1 parameter is MAXINT, or 2147483647. The Edge 2 parameter specifies the value for the second edge in a double-edge triggered trap. The default value for the Edge 2 parameter is 0.
Edge-1 Direction and Edge-2 Direction	Edge-triggered traps fire only when the edge threshold value is crossed in one direction. The Edge Direction parameters enable you to set or change the direction that is used to evaluate a trap. The edge-direction value specifies the direction (Up or Down) in which the crossover trigger is expected to occur. The default value for Edge-1 Direction is Up, and the default value for Edge-2 Direction is Down.
Interval	The Interval parameter is the time, in seconds, between evaluations of the variable associated with a trap. A trap can send data only as often as its associated variable is evaluated. The default value for the Interval parameter is 3600. Note The value of the Interval parameter for the Network Appliance predefined traps is one minute.
Interval Offset	The Interval Offset parameter is the time, in seconds, after the appliance starts up to delay the initial evaluation of this trap. This prevents too many traps from being evaluated at once immediately after the appliance starts up. The default value for the Interval Offset parameter is 0.
Rate-Interval	Enables you to specify the interval for monitoring the rate of change of a trap's MIB variable (specific object) over a period of time relative to a threshold value for that object. When the threshold is exceeded, the trigger fires the trap to notify you. Note The Interval option causes SNMP to evaluate the value of the object steadily every x number of seconds without relation to overall duration or threshold, but the Rate-Interval option causes SNMP to evaluate the object relative to a period of time that you set bounded by a threshold value. Example: You might use Rate-Interval to ensure that the amount of HTTP requests received by your appliance in one hour (360 seconds) does not exceed 90000 (requests). If the HTTP traffic surpasses that number of requests, you want to be notified (through triggering of a trap). The Rate-Interval option is used in conjunction with the Trigger option, the Edge-1 option, and the Edge-1 Direction option. These additional options enable you to define the threshold and direction for the trap variable value (object), which, if exceeded, causes a trap to fire that notifies you. (For more complex cases, you can use both directions, Edge-1 and Edge-2.) To measure the rate of HTTP requests per hour to cause a trigger to signal a trap to fire and send you a message when the threshold is exceeded, you would set the following cooperating options: Rate-Interval = 360 (seconds = 1 hour) Trigger = Single-edge trigger Edge-1 Direction = Up Edge-1 = 90000 Using the Rate-Interval option, you can scale the amount of time and the threshold values accordingly to the interval that you want to measure. Rate-Interval can be used also with Double-edge triggers, with either edge using either direction for its threshold boundary crossing. For example, you might want to use a Down direction to test for underutilization of an appliance. The default is 0.
Backoff Calculator	The Backoff Calculator parameter enables you to specify how often you want the trap evaluated after it fires the first time. After a trap fires and sends data, you might want the trap to be evaluated less frequently. For example, you might want to know when a file system is full within one minute, but want to be notified only once an hour thereafter that the file system is still full. The possible values for the Backoff Calculator parameter are as follows: Backoff Step Backoff Multiplier No Backoff The default value for the Backoff Calculator parameter is No Backoff.
Backoff Step	The Backoff Step parameter specifies the number of seconds by which the trap evaluation interval is increased. If a trap interval is 10 and its Backoff Step is 3590, the trap is evaluated every 10 seconds until it fires the first time and sends data, and is evaluated once an hour thereafter. When the trap is evaluated at the backoff step interval, the trap is fired only if the variable's value still exceeds the threshold. If the value no longer exceeds the threshold, the trap does not fire, and the trap returns to evaluating the variable with the frequency set in the Interval parameter. The default value for the Backoff Step parameter is 0.
Backoff Multiplier	The Backoff Multiplier parameter specifies the value by which to multiply a trap's evaluation interval each time the trap fires. If you set the Backoff Multiplier to Exponential Backoff and the Backoff Multiplier to 2, the evaluation interval doubles each time the trap fires. The default value for the Backoff Multiplier parameter is 1.
Priority	The Priority parameter specifies the priority of a trap. Also, if several traps are scheduled to fire at the same time, you can use the Priority parameter to decide which trap is serviced first. The possible values for the Priority parameter, in decreasing priority, are as follows: alert critical error warning notification informational debug The default value for the Priority parameter is notification.
Message	The Message parameter specifies a message that is sent out with a trap. The message could be a string of text or of the form `snmp`.oid. If an OID is specified, the result of evaluating that OID is sent. If the message parameter is not specified, the default value sent when a trap fires is a string that shows the OID value that triggered the trap. For example, the following string is sent to the network management stations for the total number of HTTP requests since last reboot: "Number of HTTP requests = <value>." Note If the message is a space-separated string, you must enclose the string in quotation marks ("").