HPE 633543-001 P420 2GB SmartArray Memory

HPE 633543-001 2GB Smart Array FBWC Cache Module for P420 and P421

HPE 633543-001 is the 2GB Flash Backed Write Cache module used on Smart Array P420 and P421 controllers. It is the cache board itself, the part that plugs onto the controller, and it is the module found inside the 631681-B21 option kit.

Engineers usually order this spare when a controller reports a cache module fault, or when a second-hand controller arrives without cache. Fitted with a working capacitor pack, it restores the protected write cache that keeps a ProLiant Gen8 array responsive under heavy writes.

You can buy the 633543-001 from Euroland IT Store in New or Refurbished condition, depending on what is in stock.

HPE 633543-001 Technical Specifications

What Is The HPE 633543-001?

This is a spare part number. HPE splits the 631681-B21 kit into its components for service, and 633543-001 covers the 2GB cache module alone. The capacitor pack is a separate part, so if your existing capacitor is healthy you only need the module.

Ordering the exact spare matters because Smart Array cache modules are not interchangeable across all generations. A Gen9 or Gen10 controller uses a different cache design, and the 1GB Gen8 module has a different number. Matching 633543-001 means the controller will recognise the cache size and enable it.

Module And Capacitor: Two Parts, One Job

The 2GB module holds data waiting to be written to disk. The capacitor pack stores energy. If the server loses power, the capacitor keeps the module running just long enough to copy everything in cache to flash memory on the module. On the next boot, the controller writes that saved data out to the drives.

If either part fails, the controller protects your data by turning write cache off. You will often see a message about the backup power source or the cache module in the POST screen or the Smart Storage Administrator. Read the message carefully. A capacitor warning points to the capacitor pack, while a cache module error points to this part.

New HPE 633543-001

A New module is the cautious choice for production servers where you want an unused cache board. It also suits refurbishers rebuilding controllers for resale. The warranty on new stock is shown on the product page.

Refurbished HPE 633543-001

Refurbished modules help keep Gen8 storage running for less. They suit one-for-one swaps when a cache module has failed. Please read the product page for refurbished condition notes and warranty.

Compatibility

• HPE Smart Array P420
• HPE Smart Array P421

Some resellers also list later P-series controllers for this module, but we have not been able to confirm that with HPE, so we do not claim it here. Check the controller model and the label on your current cache module before ordering. If your existing module is a different size, make sure the controller firmware and your planned configuration support the 2GB module.

Related Items

The full kit, module plus capacitor, is sold as HPE 631681-B21. For 1GB cache, see the refurbished HPE 631679-B21 1GB P-series FBWC and the refurbished HPE 631680-B21 1GB FBWC. Older controllers used smaller cache boards such as the HPE 462968-B21 256MB cache module and the HPE 462974-001 256MB cache module; these are not substitutes for a P420 or P421. Our RAID controller spare parts section lists more items.

Replacement Checklist

• The controller is confirmed as a P420 or P421.
• The fault message names the cache module, not the capacitor.
• The label on the removed module reads 633543-001 or shows 2GB.
• A healthy capacitor pack is already fitted, or you are ordering one too.
• The server is shut down and the power cords removed before you touch the controller.
• You have a recent backup of the array, as good practice before any storage work.

Why Replace The Cache Rather Than The Controller

A failed cache module does not mean the controller is finished. In most cases the logical drives are still intact and the controller will run in a slower, write-through mode until the cache is restored. Swapping the module is quicker and cheaper than replacing the whole card, and it avoids reconfiguring the server’s storage. Once the new module is in, check that the cache status returns to OK and that write cache is enabled again.

Buying HPE 633543-001 in the UK

Euroland IT Store has supplied server parts since 2002 to UK businesses, IT teams, resellers and repairers. The listing for this cache board spells out its condition, cover, stock position and shipping details. We ship free to the UK mainland once an order goes past £100 + VAT. Contact us with your controller and server model plus the number on your existing cache module and we will help confirm the part, or call 0203 209 6002.

633543-001 FAQs

Is the 633543-001 the same as 631681-B21?

Not exactly, because 633543-001 is the 2GB cache module on its own, while 631681-B21 is the option kit that contains this module plus a capacitor pack.

Is this module compatible with my Smart Array controller?

It is made for the Smart Array P420 and P421, so confirm your controller model and existing cache label before ordering.

Is a used cache board sold as Refurbished, and is New unused stock?

A New module is unused stock, and a Refurbished module is a previously used part sold at a lower price, with each condition described on the product page.

Where are the warranty terms shown?

The product page shows the warranty for the condition you choose.

Do you deliver to the whole of the UK?

We deliver UK wide, offer free UK mainland shipping on orders over £100 + VAT, and list delivery details on the product page.