A storage subsystem depends on more than the RAID card. The cache battery protects write-back data during a power loss, the cable connects the backplane to the controller or to the PCIe bus, and a separate HBA gives the server its path to the SAN. When one of these parts fails or goes missing, the server usually still boots, but write performance or resilience drops without much warning. This part of our Dell rack server parts and wider storage range is for engineers who already know the part number they need, and for those who still need to work it out from the hardware in front of them.
At a glance
Typical deployments
Restoring write-back cache on a PERC
A cached controller with a failed or missing battery will normally fall back to write-through. The array still works, but write-heavy workloads slow down noticeably. Match the battery to both the controller family and the form factor. The H132V battery for Mini Mono H730 and H730P cards suits the integrated version found in many 13th-generation PowerEdge servers. For 14th-generation H740 and H740P controllers, use the NWJ48 battery and bracket. Both come with the bracket, which saves hunting for a mounting point inside the chassis.
Adding NVMe bays to a PowerEdge R640
On a 10-bay SFF R640, NVMe depends on the backplane, the cabling and the PCIe enablement card working together. Plan all three before you order drives. The 6PPNG NVMe cable for bays 6 to 9 handles one group of bays. The CDC7W U.2 enablement card is a low-profile x8 card, so check that you have a free low-profile slot on the riser you intend to use. Confirm that your backplane is the NVMe-capable version for the bays you want to populate.
ZFS, Ceph and software-defined storage
When the operating system or storage layer handles redundancy, you want the disks presented directly, not hidden behind a hardware array. A cacheless SAS3 controller such as the HPE E208i-a (836259-001) or the Fujitsu CP400i is the usual choice here, because there is no controller cache that could get in the way of the file system's own write handling. Check that passthrough or HBA mode is available with the firmware you plan to run before committing to a design.
Databases and write-heavy virtual machines
For hardware RAID 5 or 6 under a database or a busy hypervisor datastore, cache size and battery health matter more than port count. A 2GB cached controller, such as the HPE Smart Array P440ar in a ProLiant, or the Cisco UCSC-RAID-M5 in a UCS C-Series, absorbs write bursts that would otherwise hit the parity calculation directly. Treat the battery as a consumable. If it is old, replacing it alongside the controller costs little compared with diagnosing intermittent write latency later.
Fibre Channel SAN connectivity
Match the HBA speed to your fabric switches and storage array ports, and plan for two paths so that multipathing can survive a card or cable fault. With single-port cards such as the Dell QLE2690 16Gb HBA (P8PCK), that means two cards in separate slots, which also protects against a slot failure. Note the bracket height: this card is full-height, so it needs a full-height riser position. Dell-branded HBAs are often searched by part number, PRNHV being a common example, and the same card can carry more than one Dell number depending on bracket and revision.
Like-for-like spares for a server estate
If you run a fleet of identical PowerEdge or ProLiant servers, keep a spare battery and a spare controller of the exact model already deployed. Using the same controller family keeps array import predictable and firmware behaviour consistent across hosts. A spare battery is one of the cheapest items in this range, and it avoids running a production host in write-through mode while you wait for a replacement.
Why buy from Compuwyze
- Orders for single parts placed before 2pm are aimed to ship the same day.
- UK delivery is normally next working day once your order has shipped.
- Free UK delivery on orders over £50, which most controller and HBA orders exceed.
- International shipping is available through FedEx economy and priority services, usually arriving in 2 to 5 days.
- Returns are accepted for 30 days, with return shipping paid by the customer.
Frequently asked questions
Will this battery fit my PERC H730P Mini?
The H132V battery with bracket is listed for the Mini Mono versions of the H730, H730P and H830. The Mini Mono is the integrated card that sits in a dedicated slot rather than a standard PCIe slot. If you have the full-height adapter version of the H730P, compare the part number on your existing battery and cable with our listing before you order. For H740 and H740P controllers, choose the NWJ48 battery instead.
Does every RAID controller need a cache battery?
No. A battery is only relevant on controllers with a cache module that you want to run in write-back mode. Cacheless cards, such as the HPE E208i-a listed here with 0GB cache, do not use one. If you are looking at an entry PERC such as the H330, check whether that controller has cache before buying a battery for it.
Can I move an existing array onto a replacement controller?
Arrays can usually be imported by a replacement controller from the same family, because the configuration is stored on the disks. On Dell PERC cards this appears as a foreign configuration that you can import. Moving between controller families or brands is less predictable. Take a verified backup first, keep the disks in their original order, and update the replacement card's firmware to the level you run elsewhere before connecting the drives.
How should I replace a failed drive module in a RAID array?
Identify the failed disk from iDRAC, iLO or the controller utility, and confirm its bay against the fault LED before you pull anything. Removing a healthy drive from a degraded RAID 5 array is the most common way to lose one. Use a replacement of the same interface and equal or greater capacity. Leave the rebuild to finish before doing any other maintenance, and expect slower performance while it runs.
I have a Dell part number such as PRNHV. How do I find the right part?
Search the store for the part number exactly as printed. Dell labels often add a leading zero, so 0PRNHV and PRNHV refer to the same item. Because one card can be sold under several Dell numbers depending on bracket height and revision, check the bracket and connector type as well as the number. If nothing matches, send us the full label details and we can tell you whether we have an equivalent.
What should I check before installing an NVMe enablement card?
Check three things: that your backplane supports NVMe in the bays you plan to use, that you have the correct cables for those bays, and that there is a free slot of the right height and width. The CDC7W is a low-profile x8 card. Update BIOS and iDRAC firmware first, as NVMe support on 14th-generation PowerEdge servers depends on current firmware.