Creating formulas

You can create custom formulas to use for discovery and data collection in addition to the formula library included with Tivoli Netcool Performance Manager DataMart.

For example, if you want to know the number of IP packets discarded on a host from MIB-II, you would use this formula:

ipInDiscards.0 + ipOutDiscards.0

where ipInDiscards.0 is the number of incoming discarded IP packets and iPOutDiscards.0 is the number of outgoing discarded IP packets.

A valid formula needs to have a MIB that is compiled in Tivoli Netcool Performance Manager DataMart. Without a valid MIB, the formula returns an error message to the request.

Editing the inventory_subelement.txt file
When you create a Discovery formula, you need to edit the Inventory_sublement.txt file to include the formula so it can be used by the Inventory tool. The Inventory_sublement.txt file lists the rules that Discovery uses and you need to create rules for any Discovery formulas you create.
Testing formulas
You can test a formula after you create it. This step is important to ensure that the formula is valid.
Saving formulas
When you save a formula, Tivoli Netcool Performance Manager DataMart searches all the MIBs that have been compiled. It creates a link from the formula to the compiled MIB containing the MIB objects used in the formula.
Modifying a custom formula
You can modify an existing formula by using the Formula Selector.

Parent topic: Writing custom formulas