The correct procedure for powering off a PowerStore appliance for hardware replacement prioritizes data integrity and system stability. First, the target node must be placed into Service Mode. This is a maintenance state that gracefully migrates all storage resources to the peer node, ensuring service continuity. After the node is successfully in service mode, a Software Shutdown is initiated through the management interface. This command ensures all running processes are terminated correctly and data in cache is written to persistent storage. Finally, once the node has fully powered down, the Power Supply Units (PSUs) can be disconnected to de-energize the chassis for safe hardware replacement.

A. Disconnect clients ® Remove PSUs ® Power off node: Removing PSUs before a graceful software shutdown constitutes a hard power-off, which risks data corruption and is not a supported procedure.

C. Software shutdown ® Disconnect network ® Service mode: A node cannot be placed into service mode after it has been shut down, as the management software required to execute the command is no longer running.

D. Remove PSUs directly: This is an improper and abrupt power removal ("pulling the plug") that bypasses all safety and data coherency mechanisms, potentially leading to data loss or hardware damage.

1. Dell PowerStore: Service Procedures Guide (Version 3.6)

Reference: In the "Power down a node" procedure

the first step listed is "Place the node that you want to power down in service mode." The subsequent steps involve issuing the power-down command (a software shutdown) and then

after confirmation

disconnecting the power cables from the PSUs. This confirms the sequence: Service Mode -> Software Shutdown -> Remove Power. (See Chapter: "Power down a node"

Page 11).

2. Dell PowerStore: Administration Guide (Version 3.6)

Reference: The guide explains the purpose of Service Mode: "Before you perform a service operation on a node

such as replacing a hardware component or shutting down the node

you must place the node in service mode." This establishes placing the node in service mode as the mandatory first step for any hardware service operation. (See Chapter: "Service and Support"

Section: "Service Mode"

Page 165).