IBM Power Hardware Center

IBM FlashSystem and FlashCore Modules Explained for AS400/IBM i Shops

IBM FlashSystem is external, SAN-attached storage built on IBM's custom FlashCore Module NVMe drives. Here is what an AS400/IBM i shop needs to know before it comes up in a Power hardware conversation.

If you administer an AS400/IBM i shop, you may hear "FlashSystem" or "FlashCore Module" come up during a Power hardware refresh or storage sizing conversation. Neither term describes something inside your AS400 or Power server itself. Both describe IBM's external, SAN-attached storage product line, which your IBM i partition can connect to once internal storage capacity or performance is no longer enough.

What Is IBM FlashSystem?

IBM FlashSystem is IBM's family of external, all-flash storage arrays. It runs on IBM's Storage Virtualize software and is a separate physical system from your IBM Power server, connected to it over a storage area network (SAN) through supported host adapters rather than installed inside the Power chassis.

For an AS400/IBM i shop, FlashSystem storage typically comes up once internal DASD capacity or throughput is exhausted, or when a business wants to consolidate storage management across IBM i and other platforms (AIX, Linux, Windows) on shared infrastructure.

What Is a FlashCore Module (FCM)?

A FlashCore Module, or FCM, is the drive technology inside a FlashSystem array. It is IBM's own NVMe drive design, built to perform compression and encryption directly in the drive's controller rather than relying on the storage system's general-purpose processors for that work. IBM markets this as a density and performance advantage over standard commodity NVMe drives.

IBM has released four FlashCore Module generations so far: FCM1, FCM2, FCM3, and FCM4. Each generation is cataloged across a capacity range from 4.8 TB up to 38.4 TB usable per module, and each capacity within a generation has its own IBM part number and feature code.

How This Connects to Your AS400/IBM i Environment

Your AS400/IBM i partition reaches FlashSystem storage the same way it reaches any external SAN storage: through a supported Fibre Channel host adapter on your Power server, with the FlashSystem array configured specifically for IBM i attachment. This is not a change to your internal DASD, your AS400 licensing, or your IBM i software stack; it is an external storage expansion or consolidation decision layered on top of your existing environment.

This usually comes up in one of two situations: your current internal storage is running out of room or performance headroom, or your organization is planning a broader Power hardware refresh and wants to evaluate external SAN storage as part of that project.

What To Ask Before You Order

If a FlashSystem quote includes FlashCore Modules, confirm three things before treating it as final: the FlashCore Module generation (FCM1 through FCM4), the usable capacity you actually need, and that the exact part number and feature code match your specific FlashSystem model. The same nominal capacity within a generation can carry more than one valid IBM part number depending on the array's frame and drawer configuration, so generation and capacity alone are not enough to confirm the order is correct.

Frequently Asked Questions

Does a FlashCore Module install inside my AS400 or Power server?
No. FlashCore Modules are installed inside external IBM FlashSystem arrays, not inside the AS400 or Power server chassis. Your IBM i partition reaches them over SAN through a Fibre Channel host adapter, the same way it would reach any other external SAN storage.
Do I need FlashSystem storage for my AS400/IBM i environment?
Not necessarily. Many AS400/IBM i shops run entirely on internal DASD storage for the life of the system. FlashSystem and FlashCore Module storage becomes relevant when internal capacity or performance is exhausted, or when a business wants to consolidate storage across multiple platforms on shared external infrastructure.
What is the difference between FCM1, FCM2, FCM3, and FCM4?
They are four successive generations of IBM's FlashCore Module NVMe drive, each with its own part numbers and feature codes across capacities from 4.8 TB to 38.4 TB. A buyer is almost always matching against an already-installed or currently quoted FlashSystem generation rather than choosing freely across all four.