HPE DL385 GEN11 8SFF X4 NVME BOX1 DA CBL - P57855-B21

HPE P57855-B21 DL385 Gen11 8SFF x4 NVMe Box 1 Direct Attach Cable

The HPE P57855-B21 is a direct attach cable (DAC) designed specifically for the HPE ProLiant DL385 Gen11 server in an 8 Small Form Factor (8SFF) drive bay configuration, routing four NVMe storage connections from Box 1. If you are building or expanding NVMe storage capacity in a DL385 Gen11, this cable is the qualified internal interconnect that keeps your drive bay-to-controller signaling on a validated path — not an aftermarket substitute.

Overview

The P57855-B21 (often searched as P57855 B21) targets system integrators and data center engineers configuring NVMe-based storage in the HPE DL385 Gen11 platform. The "x4 NVMe Box1" designation identifies the specific bay group and lane count this cable services: four NVMe lanes originating from the Box 1 drive cage in the 8SFF chassis layout. Using the correct HPE-qualified cable for this configuration avoids signal integrity issues and firmware compatibility flags that commonly appear when non-OEM cabling is substituted in HPE Gen11 platforms.

Key Features

• NVMe Interface: Carries four NVMe lanes from the Box 1 cage — the high-bandwidth, low-latency protocol that makes Gen11 all-flash configurations viable for workloads that saturate SAS/SATA throughputs.
• Platform-Specific Fit: Engineered for the DL385 Gen11 8SFF chassis geometry. The routing length and connector orientation are validated for this enclosure, removing guesswork on cable management and bend-radius clearance inside a dense 1U or 2U footprint.
• Lightweight at 0.19 lb: Minimal mass contribution in a chassis where weight budgets matter for rail and rack load calculations across multi-server deployments.
• Factory-New Genuine Component: Sourced as a genuine HPE part — no grey-market, no parallel imports — ensuring the cable carries the manufacturer warranty applicable to HPE optional components.

Compatibility

This cable is designed for use with the HPE ProLiant server line, specifically the DL385 Gen11 platform in 8SFF drive bay configurations. Consult the HPE DL385 Gen11 server accessory compatibility matrix or your HPE pre-sales engineering contact to confirm the correct cable kit for your specific drive bay and controller pairing before ordering. Mixing cable kits across Box designations (Box1 vs Box2) or lane counts (x4 vs x8) will result in an incorrect fit.

Frequently Asked Questions

Q: What server is the P57855-B21 designed for?

A: The P57855-B21 is designed specifically for the HPE ProLiant DL385 Gen11 server in an 8SFF (8 Small Form Factor) drive bay configuration, providing x4 NVMe connectivity for the Box 1 drive cage.

Q: What interface does this cable support?

A: This cable supports NVMe (Non-Volatile Memory Express), the high-speed storage protocol used with modern solid-state drives in HPE Gen11 platforms.

Q: Can this cable be used in a DL385 Gen10 or other HPE server models?

A: This cable is platform-specific to the DL385 Gen11 8SFF configuration. Compatibility with other HPE server generations or chassis variants is not verified by available evidence — confirm with HPE documentation before substituting.

Q: What does "Box 1" mean in this cable's designation?

A: In HPE DL385 Gen11 terminology, "Box 1" refers to the primary internal drive cage group. The cable routes NVMe signal lanes from that specific cage to the storage controller, distinguishing it from cables serving Box 2 or additional cage expansions.

Marty Allison

The P57855-B21 is one of those parts that looks trivial on a BOM until it's missing — then your NVMe drives in Box 1 simply don't present to the controller. This cable is the qualified x4 NVMe interconnect for the DL385 Gen11 8SFF platform, and the "Box 1" designation is not interchangeable with other cable kits in the same chassis.

Technical Highlights:

• NVMe x4 Lane Count: Four NVMe lanes per the cable designation — sized for the Box 1 drive cage in the 8SFF DL385 Gen11 configuration, not a generic multi-use cable.
• Platform-Validated Routing: HPE qualifies these cables for specific chassis geometries; the connector pitch, keying, and cable length are matched to the DL385 Gen11 internal layout — signal integrity is not an afterthought.
• 0.19 lb Weight: Light enough that it adds negligible load to a densely cabled 2U chassis, but substantial enough to confirm this is a fully-formed assembly, not a bare flex connector.

Deployment Considerations:

• Confirm the Box designation (Box 1 vs Box 2) and lane count (x4 vs x8) against your DL385 Gen11 drive cage configuration before ordering — HPE uses distinct part numbers for each combination, and the wrong cable will not reach or connect correctly.
• This part has multi-country origin (CN, CZ, JP, MX, SG, US) — relevant if your procurement process requires country-of-origin documentation for compliance or government contracts.

The right deployment for the P57855-B21 is straightforward: any DL385 Gen11 build or field-replacement requiring the Box 1 x4 NVMe internal cable. It has no role in any other platform — that specificity is exactly what makes it the correct part when you need it.