Enterprise Volume Manager (Multi-OS) Version 2.0D Network Administration Guide

Enterprise Volume Manager (Multi-OS) Network Administration Guide 5–21
Configuring the EVM Network
Available Storage Systems
To compile a list of available resources, EVM queries every StorageWorks HSG- and
HSV-based storage system in the SAN during startup and again at each periodic
storage refresh. The more storage systems involved, the longer the refresh takes to
complete.
To make this process more efficient, EVM lets users selectively filter out those storage
systems not needed for EVM jobs. When storage systems are made unavailable to
EVM, the startup and storage refresh complete more quickly.
To deselect storage systems:
1. Browse to the EVM GUI.
2. From the Resources page, click the Configuration tab.
3. From the EVM Configuration display, select the Available Storage tab.
4. In the Storage Systems section, click (uncheck) the storage systems you want to
deselect.
5. Click Update to perform the deselection.
Storage System Refresh Interval
Successful EVM job execution depends on EVM having up-to-date storage
information; periodic refreshes are critical. The following are factors to be considered
in establishing the refresh rate:
• If the storage configuration changes (for example, through the creation of a new
unit or the deletion of an existing unit), EVM will not know about the change until
a storage refresh occurs. Meanwhile, EVM jobs may fail as a result of using old
storage information.
• Refreshes are resource-intensive operations and, in extreme cases, can take as
long as five minutes per storage system to complete. So, choosing an appropriate
value for the refresh rate—one that balances performance with the need for
current information—is an important part of managing an EVM network.
• In stable environments where the storage configuration does not change
frequently, a longer refresh period ensures better performance. In environments
where storage changes frequently, a shorter refresh interval may be required.