Dell storage systems, such as PowerStore, are engineered with a high-availability, dual-node architecture. To perform maintenance on a single node, it is placed into a service mode and shut down. During this time, the peer node remains active and seamlessly takes over all I/O responsibilities for the entire appliance. This ensures that host access to data is uninterrupted, thereby maintaining redundancy and service continuity. This procedure is a fundamental aspect of non-disruptive hardware and software upgrades or replacements.

A. Shut down both nodes: This action would result in a complete system outage, directly contradicting the goal of ensuring redundancy and continuous operation.

C. Disconnect host paths: Disconnecting host paths would sever the connection between servers and the storage array, causing a loss of data access and an application outage.

D. Disable multipathing software: Multipathing software is critical for redundancy. It manages multiple I/O paths and automatically reroutes traffic to the active node if a path fails, which is essential during a node shutdown.

1. Dell Technologies White Paper. (April 2023). Dell PowerStore: High Availability. H18157.4.

Page 7

Section 3.1

"Node failure": "The PowerStore high-availability (HA) design ensures that there is no single point of failure within an appliance. If a node fails or is taken offline for maintenance

the peer node continues to service I/O for the entire appliance."

2. Dell Technologies. (June 2023). Dell PowerStore Manager Administrator's Guide for PowerStoreOS 3.6.

Chapter 10

"Service Tasks

" Section "Service Mode": "When a node is in service mode

its peer node takes over all I/O responsibilities for the appliance to ensure that data remains available."

3. Dell Technologies White Paper. (April 2023). Dell PowerStore: Introduction to the Platform. H18243.4.

Page 8

Section 2.1

"PowerStore architecture": "Each appliance has two nodes that provide high availability and data protection... If one node fails or is taken offline

the other node takes over and provides access to all resources in the appliance."