Making and Applying Configuration Changes
Read/Write and Read Only Modes
To make and apply configuration changes, the storage server making the changes must be in Read/Write mode. The current mode is displayed on the status bar. Use the Lock button 
on the toolbar to toggle between Read Only and Read/Write modes.
Refer to Read + Write/Read Only Switch for more information.
Applying the Configuration
As a safety measure, changes to the storage server configuration in the SANmelody software are first queued and require explicit acknowledgement before they go into effect. You will notice that preliminary configuration changes will first cause the affected icons to temporarily change to red until the configuration changes have been applied.
To undo any series of preliminary configuration changes before committing them, close the SANmelody interface without applying. All changes will be lost and you revert to the last applied configuration.
When satisfied with the changes, click the Apply Configuration button 
on the toolbar to apply the configuration changes and trigger the specific actions previously requested. You will receive a message confirming a successful Apply.
The Apply Configuration button is available by selecting the following components in the console tree: Storage Server, Application Server or Virtual Volumes.
To make or apply configuration changes, the storage server making the changes must be in Read/Write mode .
Partnerships
For storage server partnerships, configuration changes can be made by either storage server, but only from one storage server at a time. Before making changes on a storage server, put the machine in Read/Write mode (sometimes referred to as having the “lock”). When a storage server is in Read/Write mode, the partner storage server is prevented from making changes until the storage server making the changes puts the machine in Read Only mode ( the “lock” is released).
The best practice for storage servers is to only enable Read/Write mode during configuration changes. After changes are applied, enable Read Only mode. In this manner, either storage server can have access to making configuration changes when necessary.