Based on official Dell PowerStore technical documentation, multiple components listed are designed to be hot-swappable Field Replaceable Units (FRUs). This design ensures high availability by allowing component replacement without system downtime. Specifically, the Small Form-factor Pluggable (SFP) transceivers, the cooling fan modules, and the Battery Backup Units (BBUs) can all be safely removed and replaced while the PowerStore node is powered on and operational. The system's redundant design for power and cooling allows for these procedures without impacting overall system health.

D. Expansion IO module: This component is not hot-swappable. Official service procedures mandate that the node must be powered down or placed into service mode before replacing an I/O module.

1. Dell PowerStore Hardware Information Guide (for PowerStoreOS 3.0 and later), Page 63, "Replace a battery backup unit (BBU)". The procedure states, "The BBU is hot-swappable and can be replaced while the system is running."

2. Dell PowerStore Hardware Information Guide (for PowerStoreOS 3.0 and later), Page 61, "Replace a cooling fan module". The guide explicitly mentions, "Cooling fan modules are hot-swappable and can be replaced while the system is running."

3. Dell PowerStore Hardware Information Guide (for PowerStoreOS 3.0 and later), Page 71, "Replace an SFP or SFP+ transceiver". The document notes, "SFP and SFP+ transceivers are hot-swappable and can be replaced while the system is running."

4. Dell PowerStore Manager PowerStore T Models Service Procedures Guide, Section: "Replace an I/O module". The prerequisite steps clearly state: "Power down the node that contains the I/O module that you want to replace." This confirms that I/O modules are not hot-swappable.