HPE ProLiant SL4540 Gen8 Storage Controllers
Genuine HPE Smart Array controllers, cache modules and host bus adapters for the HPE ProLiant SL4540 Gen8, new and refurbished. Storage here is split in two: the B120i on each node drives only that node's two SFF bays, while the LFF section runs from the node's rear I/O module on an SL4500 H220 host bus adapter or a Smart Array P420i.
SL4540 Gen8 Storage Controller Specifications
- Node controller: HPE Dynamic Smart Array B120i SATA RAID, driving only that node's two 2.5-inch SFF bays
- LFF controllers: an SL4500 H220 host bus adapter or a Smart Array P420i mezzanine controller, both in the I/O module at the rear of the chassis
- How many: up to two P420i controllers per node, or only one H220 HBA
- P420i cache: 1GB or 2GB flash backed write cache plus the 12in Supercap, one set per controller — Zero Memory is not supported, and 512MB is the minimum for RAID 5, 50, 6 and 60
- P420i interface: two internal 4X SAS connectors and eight 6Gb/s SAS links for 4.8GB/s, on an x8 PCIe 3.0 connection operating at PCI 2.0, up to 64 logical drives with cache
- Add-in cards: Smart Array P421 with 1GB or 2GB FBWC and P431 with 4GB FBWC, two external SAS ports each, plus the H221 PCIe 3.0 SAS HBA
Cache is not optional on the P420i, and it is what unlocks parity RAID. Zero Memory is not supported here: every controller needs a flash backed write cache and the 12in Supercap, with 512MB the minimum before RAID 5, 50, 6 and 60 appear. Fit two P420i controllers and the PCIe enablement kit can no longer be ordered.
Which Controller Handles Which Drives?
| Controller | Where it sits | What it drives |
|---|---|---|
| Dynamic Smart Array B120i | On the server node | The two SFF SATA bays on that node only |
| SL4500 H220 host bus adapter | I/O module, rear of chassis | The node's LFF bays, one adapter per node |
| Smart Array P420i | I/O module, rear of chassis | The node's LFF bays, up to two per node |
| Smart Array P421, P431, H221 | Low profile PCIe slot | External SAS storage outside the chassis |
Read that table before buying a card rather than after. The internal path is settled by whatever the factory put in the I/O module, so a P421 or P431 does not replace an H220 or a P420i — they are two-port external cards, and they add enclosures rather than bays. What a P420i owner usually comes here for is the cache.
Choosing the Right SL4540 Gen8 Storage Controller
- A cache module alone is not a complete part. HPE pairs the 12in Super Capacity option with every P420i cache module, so the two are bought together.
- Two P420i controllers and a PCIe card are mutually exclusive. HPE states that with two fitted, the Storage Mezzanine to PCIe Enablement Kit cannot be ordered — so drive zoning costs the expansion slot.
- Drive zoning is what the second controller is for. It splits a 60-bay chassis into two 30-bay groups across ports 1i and 2i.
- RAID 6 no longer needs the Advanced Pack. HPE notes SAAP 2.0 is not required for RAID 6 and 60 on firmware 4.68 or later.
- External cards compete for one slot. A node has one low profile PCIe slot, and only one expansion option may go in it.
Complete Your SL4540 Gen8 Build
Controllers and drives are bought together — see SL4540 Gen8 drives for what the array will hold, and networking adapters if the PCIe slot is spoken for. Also available: SL4540 Gen8 memory, processors, power supplies and rack options, or the full SL4540 Gen8 parts listing. Background reading: what are HPE Flexible Smart Array controllers. Other models are listed under HPE parts by server model.
SL4540 Gen8 Storage Controllers FAQ
Which controller runs the LFF drives in an SL4540 Gen8?
Either an SL4500 H220 host bus adapter or a Smart Array P420i, both in the I/O module at the rear of the chassis. The B120i on the node handles only that node's two SFF drives.
Does the SL4540 Gen8 support RAID 5 and RAID 6?
Yes, on the Smart Array P420i with at least 512MB of cache fitted. HPE lists RAID 0, 1, 1+0, 5, 50, 6 and 60 for that controller, with the minimum cache required for the parity levels.
Can I fit a P420i without a cache module?
No. HPE states the Zero Memory cache option is not supported here, and that a cache module and the 12 inch Supercap kit must be selected for each P420i ordered.
How many P420i controllers can one node take?
Up to two, which is what enables drive zoning across ports 1i and 2i. Only one SL4500 H220 host bus adapter is supported per node.
What are the P421 and P431 controllers for?
External SAS storage. Both are two-port external cards for the low profile PCIe slot, so they reach enclosures outside the chassis rather than driving the internal LFF bays.
Why will my add-in controller not fit?
The low profile PCIe slot stays disabled until the Storage Mezzanine to PCIe Enablement Kit is fitted, and one expansion option is allowed per node. Two P420i controllers rule that kit out entirely.
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