HP 405102-B21 Smart Array E200i Controller 64MB Cache Module

Name: HP 405102-B21 Smart Array E200i Controller 64MB Cache Module
Brand: HP
SKU: 405102-B21

Add 64MB of write-back cache to your HP Smart Array E200i controller for faster RAID performance.

$471.00*

✓ In Stock on Amazon.com

*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

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Overview

The HP 405102-B21 is a 64MB cache module designed to enhance the performance of the HP Smart Array E200i RAID controller found in select HP ProLiant servers. By adding this module, the E200i controller gains the ability to use write-back caching, a technique that buffers write operations in fast onboard memory before committing them to the physical drives. This results in measurably faster write throughput, especially in RAID 5 and RAID 1+0 configurations where parity calculations and mirrored writes would otherwise create performance bottlenecks.

Installation is straightforward — the module plugs directly into the E200i controller's dedicated cache slot inside the server chassis. For data integrity during unexpected power events, HP recommends pairing the cache module with a Battery Backed Write Cache (BBWC) battery unit, which preserves cached data until power is restored and writes can be safely flushed to disk. As a legacy component for older ProLiant server generations, this cache module is most commonly used as a replacement or upgrade part in existing infrastructure environments where the E200i controller remains in service.

Key Features

012970-001, 405102-B21

Specifications

Brand

Part Number

405102-B21

Compatible Controller

HP Smart Array E200i

Cache Size

64MB

Type

Cache Module

Pros & Cons

👍 Pros

Enables write-back caching on the E200i controller for substantially improved RAID write speeds
Straightforward installation as a plug-in module for compatible HP ProLiant servers
Small 64MB capacity is sufficient for the E200i controller's design specifications

👎 Cons

Only compatible with the HP Smart Array E200i — will not work with other controller models
64MB cache is modest by modern standards and cannot be upgraded further on this controller
Requires a separate battery backup unit to safely use write-back caching
Legacy server hardware that may be difficult to find support for

Frequently Asked Questions

What controller is this cache module compatible with?

This 64MB cache module is designed specifically for the HP Smart Array E200i Controller. It is not compatible with other Smart Array controller models.

What does a cache module do for a RAID controller?

The cache module enables write-back caching on the E200i controller, allowing the controller to acknowledge write operations before they are committed to disk. This significantly improves write performance in RAID configurations.

What is the HP part number for this cache module?

This module is referenced under HP part numbers 405102-B21 and 012970-001 (also associated with spare part number 412800-001).

Does this module require a battery backup unit?

For write-back caching to function safely, a Battery Backed Write Cache (BBWC) battery is recommended to protect cached data during power loss. The battery is typically sold separately.