HP
HP 615418-B21 Smart Array P822/2G RAID Controller
★★★★★
PCIe 3.0 x8 RAID controller with 2 GB flash-backed cache delivers 6 Gb/s SAS/SATA throughput for HP server storage arrays.
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Overview
Maximize Storage Performance with Advanced RAID Technology
The HP Smart Array P822/2G FBWC RAID Storage Controller offers enhanced performance, scalability, and data protection for HP servers. With support for 6 Gbps SAS and SATA, this controller ensures reliable data management and efficient storage solutions.
- Benefits: Increased performance, scalability and data protection, with reduced initial setup time
- Bus Type: PCIe 3.0 x8
- Interface: SATA 6Gb/s / SAS 6Gb/s
Key Features
Increased performance, scalability and data protection, with reduced initial setup time
Bus Type
PCIe 3.0 x8
Interface
SATA 6Gb/s / SAS 6Gb/s
Pros & Cons
👍 Pros
- PCIe 3.0 x8 interface provides up to 4 GB/s of bus bandwidth, eliminating the controller-to-CPU data path as a bottleneck for multi-drive arrays.
- 2 GB flash-backed write cache with capacitor-based power protection removes the reliability risk and maintenance burden of battery-backed cache units.
- Support for up to 96 physical drives across internal and external mini-SAS ports enables scaling from a single server's drive bays to multi-shelf JBOD configurations.
- RAID 6 and RAID 60 support provides dual-parity protection, allowing two simultaneous drive failures per array without data loss — critical for large-capacity deployments.
👎 Cons
- 6 Gb/s SAS/SATA interface limits per-drive throughput compared to 12 Gb/s SAS controllers, which matters when using high-performance SAS SSDs that can saturate a 6 Gb/s link.
- HP firmware locks mean the controller requires HP-signed firmware updates and may not function correctly in non-HP servers or with non-HP-branded drives without workarounds.
- PCIe 3.0 x8 physical slot requirement eliminates this card from low-profile or half-height server chassis that only offer x4 or low-profile PCIe slots.
- The 2 GB FBWC module is a separate component that can fail independently — if the cache module is removed or fails, the controller falls back to write-through mode with significantly reduced write performance.
Frequently Asked Questions
Which HP server models are compatible with the P822/2G controller?
The Smart Array P822 is designed for HP ProLiant Gen8 servers, including the DL380p, DL360p, DL560, ML350p, and BL460c Gen8 blade. It installs in a full-height PCIe 3.0 x8 slot. Always verify your specific server model against HP's QuickSpecs document for the P822 before purchasing.
What RAID levels does the P822 support?
The P822 supports RAID 0, 1, 1+0, 5, 50, 6, and 60. With the 2 GB flash-backed write cache (FBWC), RAID 5 and 6 write performance is significantly improved because parity calculations can be staged in cache rather than written synchronously to disk.
What does the 2 GB flash-backed write cache actually do for performance?
The FBWC allows the controller to acknowledge write operations as complete once data reaches the cache, rather than waiting for the physical disks to confirm the write. This dramatically reduces write latency, especially for RAID 5/6 workloads. The "flash-backed" part means the cache is protected by a capacitor and flash module — if power is lost, the cache contents are saved to flash memory rather than lost, eliminating the need for a battery backup unit.
Can this controller drive both SAS and SATA disks simultaneously in the same array?
The P822 supports both SAS and SATA 6 Gb/s drives, but HP recommends against mixing SAS and SATA drives within the same logical array. You can run separate arrays — one SAS, one SATA — on different ports of the same controller without issue.
How many physical drives can the P822 address?
The P822 supports up to 96 physical drives across its internal and external SAS ports. It features two internal mini-SAS (SFF-8087) connectors and two external mini-SAS (SFF-8088) connectors, allowing connection to both internal drive bays and external JBOD enclosures for expansion.
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