Which component is an FRU?

A Battery Backup Unit (BBU) is a quintessential Field Replaceable Unit (FRU) in Dell PowerStore systems. It is a self-contained, modular component designed for on-site replacement by a field technician or a trained customer. The BBU has a finite service life and is critical for protecting cached data during a power outage. Its replacement is a common and well-documented service procedure, making it a clear example of an FRU in the context of system maintenance and serviceability.

A. DIMMs: While technically FRUs, DIMMs are sub-components located inside another major FRU (the node), making the BBU a more distinct, standalone system-level FRU.
B. Embedded IO Module: This module is an integral part of the node's mainboard. It is not a separately replaceable FRU; the entire node assembly is replaced instead.
C. Nodes: A node is a major system FRU, but the BBU is a more granular and common service part, fitting the typical scope of a component-level FRU.

1. Dell EMC PowerStore: Introduction to the Platform (White Paper, April 2022). Page 13, Section 3.1 "Node": "Each node is also connected to a BBU that is used to supply power to the node in the event of a power failure... The BBU is a field-replaceable unit (FRU)."

2. Dell PowerStore T Models Service Procedures Guide (for PowerStoreOS 3.0). The document contains a dedicated chapter, "Replace a battery backup unit," which provides step-by-step instructions for the field replacement procedure, confirming its status as an FRU.

3. Dell PowerStore T Models Hardware Information Guide (for PowerStoreOS 3.0). Page 10, Table 2 "Base enclosure components": This table explicitly lists the "Battery backup unit" as a primary, replaceable component of the base enclosure.