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Chapter 2. 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:
v PCI-X 266 system interface or PCI Express (PCIe) system interface.
v Physical link speed of 3 Gbps SAS that supports transfer rates of 300 MB per second.
v Support for SAS devices and nondisk Serial Advanced Technology Attachment (SATA) devices.
v Optimized for SAS disk configurations that use dual paths through dual expanders for redundancy
and reliability.
v Controller managed path redundancy and path switching for multiported SAS devices.
v Embedded PowerPC
Memory Access engine, and hardware finite field multiplier (FFM) DMA engine for RAID 6.
v Some adapters that support nonvolatile write cache.
v Support for RAID 5 and RAID 6 disk arrays and system mirroring.
v Supports attachment of other devices such as non-RAID disks, tape, and optical devices.
v RAID disk arrays and non-RAID devices supported as a bootable device.
v 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.
– Background parity checking.
– Background data scrubbing.
– Disks formatted to 528 bytes per sector, providing cyclical redundancy checking (CRC) and logically
bad-block checking.
– Optimized hardware for RAID 5 and 6 sequential write workloads.
– Optimized skip read-and-write disk support for transaction workloads.
v Supports a maximum of 64 advanced function disks with a maximum of 255 devices.
Note: The number of all physical SAS and SATA devices plus the number of logical RAID disk arrays
must be less than 255 per controller.
Feature comparison of SAS RAID cards
Compare the main features of PCI-X and PCI Express (PCIe) SAS RAID cards for IBM i.
The tables in this section provide a breakdown of the main features of the SAS RAID PCI-X and PCIe
controller cards.
PCI-X SAS RAID card comparison
Use the table in this topic to compare the features of PCI-X SAS RAID cards for IBM i. There are also
images of adapters for you to view.
© Copyright IBM Corp. 2009
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Reduced Instruction Set Computer (RISC) processor, hardware XOR Direct
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