SAS RAID controllers for IBM i

Find usage and maintenance information regarding controllers for the serial-attached SCSI (SAS) Redundant Array of Independent Disks (RAID) for IBM® i. Use this information with your specific system unit and operating system documentation. General information is intended for all users of this product. Service information is intended for a service representative trained on the system unit and the subsystem being serviced.

The SAS RAID controllers for IBM i have the following features:

• PCI-X 266 system interface or PCI Express (PCIe) system interface.
• Physical link speed of 3 Gbps SAS that supports transfer rates of 300 MB per second on PCI-X and PCIe adapters.
• Physical link speed of 6 Gbps SAS supporting transfer rates of 600 MB per second on PCIe2 and PCIe3 adapters.
• Support for SAS devices and nondisk Serial Advanced Technology Attachment (SATA) devices.
• Optimized for SAS disk configurations that use dual paths through dual expanders for redundancy and reliability.
• Controller managed path redundancy and path switching for SAS devices with multiple ports.
• Embedded PowerPC® Reduced Instruction Set Computer (RISC) processor, hardware XOR Direct Memory Access (DMA) engine, and hardware finite field multiplier (FFM) DMA engine for RAID 6.
• Support nonvolatile write cache for RAID disk arrays on some adapters (PCIe2 and PCIe3 adapters feature Flash-Backed-DRAM which eliminates the need for rechargeable batteries).
• Support for RAID 5 and RAID 6 disk arrays and system mirroring.
• Support for attachment of other devices such as non-RAID disks, tape, and optical devices.
• RAID disk arrays and non-RAID devices supported as a bootable device.
• Advanced RAID features:
  • Hot spares for RAID 5 and 6 disk arrays and system mirroring.
  • Ability to increase the capacity of an existing RAID 5 or 6 disk array by adding disks.
    Note: This feature is not suggested for PCIe2 and higher adapters due to performance considerations.
  • Background parity checking.
  • Background data scrubbing.
  • Disks formatted to 528 bytes per sector, providing cyclical redundancy checking (CRC) and logically bad-block checking on PCI-X and PCIe controllers.
  • Disks formatted to 528 bytes per sector, providing SCSI T10 standardized data integrity fields along with logically bad block checking on PCIe2 and PCIe3 controllers.
  • Optimized hardware for RAID 5 and 6 sequential write workloads.
  • Optimized skip read-and-write disk support for transaction workloads.
• Supports a maximum of 64 advanced function disks with a maximum of 255 devices on PCI-X and PCIe controllers.
• Supports a maximum of 240 advanced function disks with a maximum of 1023 devices on PCIe2 and PCIe3 controllers.