Sas Subsystem Configuration That Uses A Dual Storage Ioa With External Drives - IBM 8412-EAD Manual

Related concepts:
"SAS subsystem service considerations" on page 12
There are several considerations to review before servicing features within the SAS subsystem for the
8412-EAD, 9117-MMB, 9117-MMC, 9117-MMD, 9179-MHB, 9179-MHC, or 9179-MHD system.
"Service considerations for the 175 MB cache RAID - dual IOA enablement card" on page 13
To prevent data loss, follow proper procedures before replacing the 175 MB cache RAID – dual IOA
enablement card.
"Service considerations for the cache battery pack" on page 14
To prevent data loss, follow proper procedures before replacing the cache battery pack on the 175 MB
cache RAID – dual IOA enablement card.
SAS subsystem configuration that uses a dual storage IOA with
external drives
This configuration uses dual storage I/O adapter (IOA) or high availability (HA) RAID mode with
internal and external disk drives.
You can increase availability by using high availability to connect multiple adapters to a common set of
internal disk drives and external disk enclosures. The following rules apply to this configuration:
v This configuration uses the 175 MB Cache RAID – Dual IOA enablement card.
v The two SAS adapters with write cache can connect to each other, connect to the six internal disk
drives, and connect to the 12 disk drives in an external disk drive enclosure by using the dual IOA
enablement card and the external SAS port.
v Only hard disk drives (HDDs) are supported in this configuration. You cannot use solid-state drives
(SSDs).
v The disk drives are required to be in RAID arrays.
v RAID 0, 10, 5, and 6 are supported.
v No separate SAS cables are required to connect the two embedded SAS RAID adapters to each other.
The connection is contained within the backplane.
v The 5886 disk drive enclosure provides external storage in this configuration.
Example: Dual storage IOA using external drives
This example provides an overview of the dual storage IOA configuration that uses external disk drives.
Figure 6. Disk bays controlled by both embedded SAS adapters when using dual storage IOA with internal and
external drives
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SAS subsystem