Optimizing data collection for the Dataset Attributes Database feature
Follow these guidelines to optimize use of the Dataset Attribute Database feature:
- In a multi-system, shared hard-disk-drive environment, only enable Dataset Attribute collection on one of the connected systems, ideally a non-production system. This approach avoids collection of the same data set space information on multiple systems, and places the work for collection on the most lightly loaded system.
- Use product-provided queries and workspaces rather than user-created, as they have been crafted and tuned for maximum performance. User-defined queries can incur significant overhead if a very large number of data sets needs to be examined to resolve the predicates.
- User-created situations written against the Dataset Detail table run against the complete data set database. Do not set a Situation Sampling Interval smaller than the Dataset Attribute Database collection cycle, because attributes in the database are not updated more often than that.
- In OMEGAMON® for Storage version 4.2.0 Interim Feature 2.0, you can define a dataset attribute group to logically group a related set of data sets. When you craft a group, define the properties and attributes such that they limit the number of data sets that make up the group. If a large number of data sets in the Dataset Attribute Database match the criteria for your group, or a large number of data sets must to be examined to determine whether they match the criteria, this activity can require excessive processing, network and space resources.
- VSAM data sets are typically reported under their cluster name in the Dataset Attribute Database workspaces. Although the data sets contain a cluster component, a data component and an index component, these components are counted as a single data set in the Dataset Attribute Database workspaces. In addition, only the cluster component name displays in the table views to represent the data set. In counters displaying the "Total Datasets" in a group, a single VSAM data set is counted only once. Note that after a VSAM data set has been migrated, the cluster, data and index components are treated as individual data sets by the Dataset Attribute Database workspaces. Each component appears on a separate line in table views. In counters displaying the "Total Datasets" in a group, each component is counted separately, increasing the data set count (in contrast to the count prior to migration). This discrepancy occurs because the catalog entry for a VSAM dataset is changed after the data set is migrated. The catalog entry change causes an inaccurate count. In fact, the Catalog Search Index reports these component names as type 'A' (Non-VSAM data sets).