Differences between PDS V1 and PDS V2

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Version 2 of the persistent data store (PDS V2) replaces the original persistent data store (PDS V1). This topic outlines some of the differences between PDS V1 and PDS V2.

PDS V2 provides enhancements for near-term history collection in the OMEGAMON® products. For example, PDS V2 uses significantly less 31-bit virtual storage and less CPU usage than PDS V1, and has resulted in improved performance. In addition, PDS V2 uses VSAM linear data sets, whereas PDS V1 uses BSAM data sets.

If the Tivoli Enterprise Monitoring Server or the Tivoli Enterprise Monitoring Agent is running on z/OS® 2.2 with APAR OA50569 or later, then PDS V2 is automatically used instead of the original PDS V1.

The following table summarizes differences between PDS V2 and the original PDS V1:

Table 1. Differences between PDS V1 and PDS V2
Characteristic PDS V1 PDS V2
Underlying data set type BSAM VSAM Linear Data Sets (LDSs)
Supported z/OS version Any z/OS version Requires z/OS 2.2 with APAR OA50569 or later
How data sets are allocated The user runs a batch job. The data sets are defined dynamically from within the monitoring server or the monitoring agent. For more information, see About PDS V2 data sets and statuses.
Action when a data set is full Recording rolls over to the next data set. A batch job is generated automatically to allocate a new data set. For space-based mode (ECR=NO), the switch to the next empty data set occurs when the current data set runs out of space. No extents are taken when the current data set is full.

For time-based mode (ECR=YES), each LDS contains data for a single 24-hour period. When an LDS is full and cannot be extended, recording rolls over to the next data set and less than 24 hours of data may be present in the data set.

Virtual storage usage Uses 31-bit virtual storage heavily The monitoring server and the monitoring agent use 64-bit virtual storage above the bar.
Data set name low-level qualifier
For the monitoring server:
  • RppSGRPn
  • RPDSGRPn
  • RGENHISn
For monitoring agents:
  • RKppaaan
where:
  • pp is the two-character OMEGAMON product or component code
  • aaa varies by product
  • n is a sequential identifier number (0-9, A-Z)

See PDS data set names for more information.

 Gppmnnnn, Hppmnnnn
where:
  • pp is the two-character OMEGAMON product or component code
  • m is the granularity level (0-4). This information is for internal use.
  • nnnn is a sequential, rotating number (0-9, A-Z), or CONF for the configuration file

See PDS data set names for more information.
Attribute groups The data written to the persistent data store is organized by tables (attribute groups), groups, and data sets. Each table is assigned to a group. Multiple tables can be assigned to each group, and each group can have one or more data sets assigned to it. By default, six data sets are assigned to a group. Attribute groups are no longer organized into separate groups, and data sets are no longer assigned to groups.

Instead, all attribute groups for an application are effectively in a single data store group.
Extended address volume (EAV) support Does not support EAV Supports EAV
z/OS® data set encryption support Does not support z/OS® data set encryption Supports z/OS® data set encryption
Management and maintenance Manual process Self-managed