IBM 74Y4064 Handbook page 99

allow the physical links to be used in various narrow and wide-port configurations. The adapter does not
have a non-volatile write cache. However, Linux customers can take advantage of a volatile adapter write
cache of up to 1 Gb (compressed) for improved performance. This support is available with the 2.4.10
version of the iprutils utility available from the IBM Linux Power Tools Repository
(http://www14.software.ibm.com/webapp/set2/sas/f/lopdiags/yum.html) and with the latest adapter
firmware available from the Fix Central website (http://www.ibm.com/support/fixcentral/).
The adapter is a 64 bit, 3.3 V, bootable SAS adapter that provides RAID 0, 5, 6, and 10 capability, and
system level mirroring via the operating system. The adapter provides both single and dual RAID
controller configurations. Dual controller configurations (dual storage IOA) must run RAID. JBOD (512
byte) functionality is supported only in a single controller configuration based on the operating system.
Best performance is achieved when multiple RAID sets are configured and optimized under a pair of
adapters in a high availability, multi-initiator RAID configuration (dual storage IOA) which allows for an
Active-Active mode of operation.
The adapter supports a maximum of 96 attached disk devices that depends on the drive enclosure
attached. A maximum of 48 devices can be solid-state devices (SSDs). Externally attached devices are
designed to run at a maximum data rate of 6 Gbps for SAS disk devices. This adapter supports RAID
and non-RAID DASD. Specific device attachment support rules apply. This adapter supports the
multi-initiator and high availability (dual storage IOA) configurations in AIX, IBM i, and Linux
partitions.Linux. This adapter enables configuring the SAS drives as dedicated hot-spares with equal or
higher capacity.
Important: For more information, see the SAS RAID controllers for AIX, SAS RAID controllers for IBM i,
or SAS RAID controllers for Linux topics for more information and important considerations for
multi-initiator and high availability or dual storage IOA configurations.
Figure 37 shows the adapter. The connector plug (A) is installed in an empty port and prevents damage
to that port whenever a cable for the adjacent port connectors is plugged-in or removed.
Figure 37. PCIe3 RAID SAS quad-port 6 Gb LP Adapter
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Managing PCIe adapters