Specifications

Chapter 2. Architecture and technical overview 93
򐂰 IBM 7031 TotalStorage EXP24 Ultra320 SCSI Expandable Storage Disk Enclosure
(no longer orderable)
򐂰 IBM System Storage
Table 2-29 on page 85 provides an overview of SAS external disks subsystems.
Table 2-34 I/O drawer capabilities
2.11.1 EXP 12S Expansion Drawer
The EXP 12S (#5886) is an expansion drawer with twelve 3.5-inch form factor SAS bays.
#5886 supports up to 12 hot-swap SAS HDDs or up to eight hot-swap SSDs. The EXP 12S
includes redundant ac power supplies and two power cords. Though the drawer is one set of
12 drives, which is run by one SAS controller or one pair of SAS controllers, it has two SAS
attachment ports and two service managers for redundancy. The EXP 12S takes up a 2 EIA
space in a 19-inch rack. The SAS controller can be a SAS PCI-X or PCIe adapter or pair
of adapters.
The drawer can either be attached using the backplane, providing an external SAS port, or
using one of the following adapters:
򐂰 PCIe 380 MB Cache Dual -x4 3 Gb SAS RAID adapter (#5805)
򐂰 PCI-X DDR Dual -x4 SAS adapter (#5900 is supported but no longer orderable)
򐂰 PCIe Dual -x4 SAS adapter (#5901)
򐂰 PCIe 380 MB Cache Dual -x4 3 Gb SAS RAID adapter (#5903 is supported but no longer
orderable)
򐂰 PCI-X DDR 1.5 GB Cache SAS RAID adapter (#5904)
򐂰 PCI-X DDR Dual -x4 SAS adapter (#5912)
򐂰 PCIe2 1.8 GB Cache RAID SAS Adapter (#5913)
The SAS disk drives or SSD contained in the EXP 12S Expansion Drawer are controlled by
one or two PCIe or PCI-X SAS adapters connected to the EXP 12S Expansion Drawer
through SAS cables. The SAS cable varies, depending on the adapter being used, the
operating system being used, and the protection desired.
The large cache PCI-X DDR 1.5 GB Cache SAS RAID Adapter (#5904) and PCI-X DDR
1.5 GB Cache SAS RAID Adapter (BSC) (#5908) uses a SAS Y cable when a single port is
running the EXP 12S Expansion Drawer. A SAS X cable is used when a pair of adapters is
used for controller redundancy.
The medium cache PCIe 380 MB Cache Dual - x4 3 Gb SAS RAID Adapter (#5903) is always
paired and uses a SAS X cable to attach the feature #5886 I/O drawer.
The zero cache PCI-X DDR Dual - x4 SAS Adapter (#5912) and PCIe Dual-x4 SAS Adapter
(#5901) use a SAS Y cable when a single port is running the EXP 12S Expansion Drawer. A
SAS X cable is used for AIX or Linux environments when a pair of adapters is used for
controller redundancy.
Drawer
feature code
DASD PCI slots Requirements for a
Power 770 and Power 780
#5886 12 x SAS disk drive bays - Any supported SAS adapter
#5887 24x - Any supported SAS adapter