Tuning your storage allocation for IBM Tivoli Monitoring and OMEGAMON XE software
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Article Date: 01 Aug 2009
There are different storage parameters in IBM Tivoli Management Services: Engine (ITMS:Engine) that are set for different products. There seems to be no real consistency between the various OMEGAMON products. Because we feel these values are important to performance, we want to be sure that they are set correctly. Are these parameters load-dependent, and if yes, do you have recommended values for these parameters? What is the risk when they are too high? What is the risk when they are too low? – Zealous in Zollikofen
IBM Tivoli Management Services: Engine (ITMS:Engine) is a common component for both the Tivoli Enterprise Monitoring Server and the Tivoli Enterprise Monitoring Agents. The default parameters are defined in the data set pointed to by the RKLVIN DD statement in the started task procedure.
ITMS:Engine MAXMUM parameter
The MAXIMUM parameter is used to specify the maximum amount (in KB) of extended storage that can be allocated. This value for primary storage and for extended storage is specified as a power of 2. The maximum value that you specify for each type of storage request (primary and extended) can be no higher than 25 (32768 KB). The default MAXIMUM for extended storage is 23 (8192 KB). The default MAXIMUM for primary storage is 16 (64 KB). Some Tivoli Enterprise Monitoring Agents that are configured to run in the Tivoli Enterprise Management Server address space require a MAXIMUM primary storage request size of 20 (1 MB). When managing a large number of resources, a value of MAXIMUM(32768 KB) is recommended.
ITMS:Engine LIMIT parameter
The LIMIT parameter can be used to specify the largest block of primary storage or extended storage that can be allocated. The syntax for setting the largest block of extended and primary storage is shown below:
This value is specified in bytes, as a power of 2. For example, if n is 22, the largest block that can be allocated is 4 MB. If the LIMIT value is too small and a process in ITMS:Engine attempts to allocate a block of storage larger allowed by LIMIT, a program interruption U0100 or U0200 results When managing a large number of resources, a value of LIMIT(25,X) and LIMIT(20,P) is recommended.
ITMS:Engine MINIMUM parameter
The MINIMUM parameter is used to specify the minimum amount (in KB) of extended storage that can be allocated. This value is specified with this syntax:
MINIMUM(8192,X | n,X)
Where n represents the minimum amount of extended storage (in KB) that can be allocated. For example, to specify a 16MB above-the-line region, code MINIMUM(16384,X). When managing a large number of resources, a value of MINIMUM(768000,X) is recommended.
You may also need to specify a larger values if any of your monitoring agents builds large VTAM request/response units (RUs) and data streams.
If a program requests a block of storage larger than the MAXIMUM value set, an abend occurs. The MAXIMUM value is used in building storage access tables to speed memory allocation. Too small a value causes the ITMS:Engine components to fail. Too large a value wastes storage and increases processing overhead.