The statement is correct. In a Dell PowerFlex system, placing a Storage Data Server (SDS) node into Maintenance Mode is the standard procedure before performing maintenance or removing it from the cluster. This action initiates a graceful data migration process where all data residing on the target SDS is rebuilt and copied to other SDSs within the same Storage Pool and Protection Domain. This ensures that full data redundancy and protection are restored before the node is taken offline, thereby preventing any impact on data availability for connected clients.

The "False" option is incorrect because the primary function of Maintenance Mode is precisely to prevent data unavailability. Failing to use Maintenance Mode before shutting down or removing an SDS node would trigger an emergency rebuild process, which could impact performance and, in scenarios with pre-existing faults, potentially risk data availability. Maintenance Mode provides a controlled, non-disruptive method for handling planned node outages.

1. Dell PowerFlex Administration Guide (Version 4.x): In the chapter on "Maintaining the system

" the section "Placing an SDS into maintenance mode" details the procedure. It states

"When you place an SDS into maintenance mode

the system rebuilds the data that was on that SDS onto other SDSs in the same protection domain. This ensures that the data remains protected and accessible while the SDS is offline for maintenance." This confirms that the process is designed to maintain data availability.

2. Dell PowerFlex CLI Reference Guide (Version 4.x): The description for the scli --entermaintenancemode command explains its function. It clarifies that this command initiates a data rebuild to ensure data is moved off the specified SDS. The command's successful completion indicates that the data has been migrated and the SDS can be safely shut down without affecting data access.

3. Dell PowerFlex Concepts and Architecture Guide (Version 4.x): The guide's section on "Data Protection and Rebuilds" explains the difference between graceful procedures (like Maintenance Mode) and failure-induced rebuilds. It highlights that Maintenance Mode is a planned activity that leverages the system's self-healing capabilities in a controlled manner to avoid service disruption

which is central to the concept of maintaining data availability.