GLVM DR Sizing tool

The performance of a volume group in an asynchronous Geographical Logical Volume Manager (GLVM) is affected by the bandwidth between sites and the cache configuration of a logical volume. For system requirement updates, you must monitor the network and performance of data replication of the GLVM volume group.

In PowerHA® SystemMirror® Version 7.2.7, the GLVM disaster recovery (DR) Sizing tool is used to monitor data replication and to provide suitable recommendations.

The GLVM DR Sizing tool performs the following functions:
  • Collects the data writes and cache information for the local and remote sites.
  • Analyzes the collected data.
  • Provides recommendations to optimize the cache size and the network bandwidth.
start of changeStarting with PowerHA SystemMirror Version 7.2.8, and later, the GLVM DR Sizing tool can use the iPerf tool to provide suitable network latency recommendations. The iPerf tool has the following functions:
  • Creates a server on the home node, with all the remote nodes connecting to this server.
  • Transfer data packets on the network and collect network performance statistics.
  • Provide information about network bandwidth and network latency.
Note: To get the network latency recommendations, you must use the iPerf tool version 2.0.9 on all virtual machines. For more information, see the iPerf Tool.
end of change

The GLVM DR Sizing tool includes the cl_survey utility that is used to evaluate the current disk usage on the system. The cl_survey utility provides information to specific network that has sufficient bandwidth that can be used in an asynchronous GLVM volume group. The cl_survey utility works similar to UNIX performance monitoring programs (for example, the clperfstat program). For more information, see the cl_survey command.

The GLVM DR Sizing tool has the following limitations:
  • An asynchronous GLVM must be configured in PowerHA SystemMirror, and the cluster services must be in the STABLE state.
  • You cannot run the tool multiple times.
  • Raw logical volumes are not supported.
  • You must not change the configuration when the cl_survey tool is running. The cl_survey tool might stop if it detects any configuration changes when it is running.