IBM Power ESE 8412-EAD, Manual

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v
Each SAS adapter can recognize only three of the disk drives and cannot function in dual storage I/O
adapter (IOA) or high availability (HA) RAID mode. One SAS adapter connects to D1, D2, and D3. The
other SAS adapter connects to D4, D5, and D6.
v
The SAS adapters can be assigned to separate partitions for boot devices.
v
This configuration supports disks without RAID (referred to as JBOD) or RAID drives. However, RAID
drives are limited to three drives and no write cache.
v
RAID 10 with two drives is limited. A RAID 10 array with two drives is equivalent to RAID 1
(mirrored drives). A RAID 0 disk array with one drive is similar to JBOD support. A RAID 10 array
with one or three drives is not allowed.
v Solid-state drives (SSDs) and hard disk drives (HDDs) can be used, but they can never be mixed in the
same disk enclosure.
v
SSD and HDD can both be present in a split backplane if each side of the split backplane has only SSD
or HDD.
Example: Two-way split backplane
This example shows a two-way split backplane configuration. Each embedded SAS adapter controls three
disk drives.
The following table lists the details of the two-way split backplane configuration.
Table 3. Configuration details
Embedded SAS adapter Configuration details
Embedded SAS adapter A
v
The SAS adapter connects to disk drive D1, D2, and
D3.
v
Physical connections to the SAS cable are disabled. If
the external SAS port is installed, it is not functional.
v
The SAS adapter reports CCIN 57C7.
Embedded SAS adapter B
v
The SAS adapter connects to disk drive D4, D5, and
D6.
v
Physical connections to the SAS cable are disabled. If
the external SAS port is installed, it is not functional.
v The SAS adapter reports CCIN 57C7.
SAS subsystem configuration that uses a three-way split backplane
This topic provides rules and examples of a configuration that uses a three-way split backplane.
The following rules apply to this configuration:
Figure 2. Disk bays controlled by each embedded SAS adapter in a two-way split backplane
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SAS subsystem