Bull Escala Power7 Series User manual

SAS subsystem for the M6-700, M6-705,
M6-715, M7-700, M7-705 or M7-715
ESCALA Power7
REFERENCE
86 A1 04FG 05

ESCALA Models Reference
The ESCALA Power7 publications concern the following models:
Bull Escala E1-700 / E3-700 (31E/2B ,8231-E2B)
Bull Escala E1-705 (31E/1C, 8231-E1C)
Bull Escala E1-715 (31E/1D, 8231-E1D)
Bull Escala E3-705 (31E/2C, 8231-E2C)
Bull Escala E3-715 (31E/2D, 8231-E2D)
Bull Escala E2-700 / E2-700T (02E/4B, 8202-E4B)
Bull Escala E2-705 / E2-705T (02E/4C, 8202-E4C)
Bull Escala E2-715 / E2-715T (02E/4D, 8202-E4D)
Bull Escala E4-700 / E4-700T (05F/6B, 8205-E6B)
Bull Escala E4-705 (05E/6C, 8205-E6C)
Bull Escala E4-715 (05E/6D, 8205-E6D)
Bull Escala E5-700 (33E/8B, 8233-E8B)
Bull Escala E5-715 (08E/8D, 8408-E8D)
Bull Escala M5-715 (09R/MD, 9109-RMD)
Bull Escala M6-700 (17M/MB, 9117-MMB)
Bull Escala M6-705 (17M/MC, 9117-MMC)
Bull Escala M6-715 (17M/MD, 9117-MMD)
Bull Escala M7-700 (79M/HB, 9179-MHB)
Bull Escala M7-705 (79M/HC, 9179-MHC)
Bull Escala M7-715 (79M/HD, 9179-MHD)
Bull Escala H9-700 (19F/HB, 9119-FHB)
References to 8236-E8C models are irrelevant.
Hardware
February 2013
BULL CEDOC
357 AVENUE PATTON
B.P.20845
49008 ANGERS CEDEX 01
FRANCE

The following copyright notice protects this book under Copyright laws which prohibit such actions as, but not limited to, copying,
distributing, modifying, and making derivative works.
Copyright © Bull SAS 2013
Printed in France
Trademarks and Acknowledgements
We acknowledge the rights of the proprietors of the trademarks mentioned in this manual.
All brand names and software and hardware product names are subject to trademark and/or patent protection.
Quoting of brand and product names is for information purposes only and does not represent trademark misuse.
The information in this document is subject to change without notice. Bull will not be liable for errors contained herein, or
for incidental or consequential damages in connection with the use of this material.

Contents
Safety notices .................................v
SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD ....1
SAS architecture ..................................1
SAS subsystem overview ..............................1
SAS storage configurations ..............................4
SAS subsystem configuration that uses a two-way split backplane ................5
SAS subsystem configuration that uses a three-way split backplane ................6
SAS subsystem configuration that uses a dual storage IOA with internal drives ............8
SAS subsystem configuration that uses a dual storage IOA with external drives ............9
SAS subsystem service considerations ..........................12
Service considerations for the internal SAS cable for a three-way split backplane ...........12
Service considerations for the 175 MB cache RAID - dual IOA enablement card ...........13
Service considerations for the cache battery pack ......................14
Problem determination and recovery ...........................15
Notices ...................................17
Trademarks ...................................18
Electronic emission notices ..............................18
Class A Notices .................................18
Class B Notices .................................22
Terms and conditions ................................24
iii

iv SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

Safety notices
Safety notices may be printed throughout this guide:
vDANGER notices call attention to a situation that is potentially lethal or extremely hazardous to
people.
vCAUTION notices call attention to a situation that is potentially hazardous to people because of some
existing condition.
vAttention notices call attention to the possibility of damage to a program, device, system, or data.
World Trade safety information
Several countries require the safety information contained in product publications to be presented in their
national languages. If this requirement applies to your country, a safety information booklet is included
in the publications package shipped with the product. The booklet contains the safety information in
your national language with references to the U.S. English source. Before using a U.S. English publication
to install, operate, or service this product, you must first become familiar with the related safety
information in the booklet. You should also refer to the booklet any time you do not clearly understand
any safety information in the U.S. English publications.
German safety information
Das Produkt ist nicht für den Einsatz an Bildschirmarbeitsplätzen im Sinne§2der
Bildschirmarbeitsverordnung geeignet.
Laser safety information
IBM®servers can use I/O cards or features that are fiber-optic based and that utilize lasers or LEDs.
Laser compliance
IBM servers may be installed inside or outside of an IT equipment rack.
v

DANGER
When working on or around the system, observe the following precautions:
Electrical voltage and current from power, telephone, and communication cables are hazardous. To
avoid a shock hazard:
vConnect power to this unit only with the provided power cord. Do not use the provided power
cord for any other product.
vDo not open or service any power supply assembly.
vDo not connect or disconnect any cables or perform installation, maintenance, or reconfiguration
of this product during an electrical storm.
vThe product might be equipped with multiple power cords. To remove all hazardous voltages,
disconnect all power cords.
vConnect all power cords to a properly wired and grounded electrical outlet. Ensure that the outlet
supplies proper voltage and phase rotation according to the system rating plate.
vConnect any equipment that will be attached to this product to properly wired outlets.
vWhen possible, use one hand only to connect or disconnect signal cables.
vNever turn on any equipment when there is evidence of fire, water, or structural damage.
vDisconnect the attached power cords, telecommunications systems, networks, and modems before
you open the device covers, unless instructed otherwise in the installation and configuration
procedures.
vConnect and disconnect cables as described in the following procedures when installing, moving,
or opening covers on this product or attached devices.
To Disconnect:
1. Turn off everything (unless instructed otherwise).
2. Remove the power cords from the outlets.
3. Remove the signal cables from the connectors.
4. Remove all cables from the devices.
To Connect:
1. Turn off everything (unless instructed otherwise).
2. Attach all cables to the devices.
3. Attach the signal cables to the connectors.
4. Attach the power cords to the outlets.
5. Turn on the devices.
(D005a)
DANGER
vi SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

Observe the following precautions when working on or around your IT rack system:
vHeavy equipment–personal injury or equipment damage might result if mishandled.
vAlways lower the leveling pads on the rack cabinet.
vAlways install stabilizer brackets on the rack cabinet.
vTo avoid hazardous conditions due to uneven mechanical loading, always install the heaviest
devices in the bottom of the rack cabinet. Always install servers and optional devices starting
from the bottom of the rack cabinet.
vRack-mounted devices are not to be used as shelves or work spaces. Do not place objects on top
of rack-mounted devices.
vEach rack cabinet might have more than one power cord. Be sure to disconnect all power cords in
the rack cabinet when directed to disconnect power during servicing.
vConnect all devices installed in a rack cabinet to power devices installed in the same rack
cabinet. Do not plug a power cord from a device installed in one rack cabinet into a power
device installed in a different rack cabinet.
vAn electrical outlet that is not correctly wired could place hazardous voltage on the metal parts of
the system or the devices that attach to the system. It is the responsibility of the customer to
ensure that the outlet is correctly wired and grounded to prevent an electrical shock.
CAUTION
vDo not install a unit in a rack where the internal rack ambient temperatures will exceed the
manufacturer's recommended ambient temperature for all your rack-mounted devices.
vDo not install a unit in a rack where the air flow is compromised. Ensure that air flow is not
blocked or reduced on any side, front, or back of a unit used for air flow through the unit.
vConsideration should be given to the connection of the equipment to the supply circuit so that
overloading of the circuits does not compromise the supply wiring or overcurrent protection. To
provide the correct power connection to a rack, refer to the rating labels located on the
equipment in the rack to determine the total power requirement of the supply circuit.
v(For sliding drawers.) Do not pull out or install any drawer or feature if the rack stabilizer brackets
are not attached to the rack. Do not pull out more than one drawer at a time. The rack might
become unstable if you pull out more than one drawer at a time.
v(For fixed drawers.) This drawer is a fixed drawer and must not be moved for servicing unless
specified by the manufacturer. Attempting to move the drawer partially or completely out of the
rack might cause the rack to become unstable or cause the drawer to fall out of the rack.
(R001)
Safety notices vii

CAUTION:
Removing components from the upper positions in the rack cabinet improves rack stability during
relocation. Follow these general guidelines whenever you relocate a populated rack cabinet within a
room or building:
vReduce the weight of the rack cabinet by removing equipment starting at the top of the rack
cabinet. When possible, restore the rack cabinet to the configuration of the rack cabinet as you
received it. If this configuration is not known, you must observe the following precautions:
– Remove all devices in the 32U position and above.
– Ensure that the heaviest devices are installed in the bottom of the rack cabinet.
– Ensure that there are no empty U-levels between devices installed in the rack cabinet below the
32U level.
vIf the rack cabinet you are relocating is part of a suite of rack cabinets, detach the rack cabinet from
the suite.
vInspect the route that you plan to take to eliminate potential hazards.
vVerify that the route that you choose can support the weight of the loaded rack cabinet. Refer to the
documentation that comes with your rack cabinet for the weight of a loaded rack cabinet.
vVerify that all door openings are at least 760 x 230 mm (30 x 80 in.).
vEnsure that all devices, shelves, drawers, doors, and cables are secure.
vEnsure that the four leveling pads are raised to their highest position.
vEnsure that there is no stabilizer bracket installed on the rack cabinet during movement.
vDo not use a ramp inclined at more than 10 degrees.
vWhen the rack cabinet is in the new location, complete the following steps:
– Lower the four leveling pads.
– Install stabilizer brackets on the rack cabinet.
– If you removed any devices from the rack cabinet, repopulate the rack cabinet from the lowest
position to the highest position.
vIf a long-distance relocation is required, restore the rack cabinet to the configuration of the rack
cabinet as you received it. Pack the rack cabinet in the original packaging material, or equivalent.
Also lower the leveling pads to raise the casters off of the pallet and bolt the rack cabinet to the
pallet.
(R002)
(L001)
(L002)
viii SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

(L003)
or
All lasers are certified in the U.S. to conform to the requirements of DHHS 21 CFR Subchapter J for class
1 laser products. Outside the U.S., they are certified to be in compliance with IEC 60825 as a class 1 laser
product. Consult the label on each part for laser certification numbers and approval information.
CAUTION:
This product might contain one or more of the following devices: CD-ROM drive, DVD-ROM drive,
DVD-RAM drive, or laser module, which are Class 1 laser products. Note the following information:
vDo not remove the covers. Removing the covers of the laser product could result in exposure to
hazardous laser radiation. There are no serviceable parts inside the device.
vUse of the controls or adjustments or performance of procedures other than those specified herein
might result in hazardous radiation exposure.
(C026)
Safety notices ix

CAUTION:
Data processing environments can contain equipment transmitting on system links with laser modules
that operate at greater than Class 1 power levels. For this reason, never look into the end of an optical
fiber cable or open receptacle. (C027)
CAUTION:
This product contains a Class 1M laser. Do not view directly with optical instruments. (C028)
CAUTION:
Some laser products contain an embedded Class 3A or Class 3B laser diode. Note the following
information: laser radiation when open. Do not stare into the beam, do not view directly with optical
instruments, and avoid direct exposure to the beam. (C030)
CAUTION:
The battery contains lithium. To avoid possible explosion, do not burn or charge the battery.
Do Not:
v___ Throw or immerse into water
v___ Heat to more than 100°C (212°F)
v___ Repair or disassemble
Exchange only with the approved part. Recycle or discard the battery as instructed by local
regulations. (C003a)
Power and cabling information for NEBS (Network Equipment-Building System)
GR-1089-CORE
The following comments apply to the IBM servers that have been designated as conforming to NEBS
(Network Equipment-Building System) GR-1089-CORE:
The equipment is suitable for installation in the following:
vNetwork telecommunications facilities
vLocations where the NEC (National Electrical Code) applies
The intrabuilding ports of this equipment are suitable for connection to intrabuilding or unexposed
wiring or cabling only. The intrabuilding ports of this equipment must not be metallically connected to the
interfaces that connect to the OSP (outside plant) or its wiring. These interfaces are designed for use as
intrabuilding interfaces only (Type 2 or Type 4 ports as described in GR-1089-CORE) and require isolation
from the exposed OSP cabling. The addition of primary protectors is not sufficient protection to connect
these interfaces metallically to OSP wiring.
Note: All Ethernet cables must be shielded and grounded at both ends.
The ac-powered system does not require the use of an external surge protection device (SPD).
The dc-powered system employs an isolated DC return (DC-I) design. The DC battery return terminal
shall not be connected to the chassis or frame ground.
xSAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB,
79M/HC, or 79M/HD
Review the SAS subsystem features, configurations, and limitations for the 7/70 (17M/MB, 17M/MC, or
17M/MD) and the 7/80 (79M/HB, 79M/HC, or 79M/HD) system.
SAS architecture
Serial-attached SCSI (SAS) architecture describes a serial device interconnection and transportation
protocol that defines the rules for information exchange between devices.
SAS is an evolution of the parallel SCSI device interface into a serial point-to-point interface. SAS
physical links are a set of four wires used as two differential signal pairs. One differential signal transmits
in one direction, while the other differential signal transmits in the opposite direction. Data can be
transmitted in both directions simultaneously. Physical links are contained in SAS ports, which contain
one or more physical links. If there is more than one physical link in the port, the port is a wide port. If
there is only one physical link in the port, it is a narrow port. A port is identified by a unique SAS
worldwide name (also called SAS address).
ASAS adapter contains one or more SAS ports. A path is a logical point-to-point link between a SAS
initiator port in the adapter and a SAS target port in the I/O device (for example, a disk). A connection is
a temporary association between an adapter and an I/O device through a path. A connection enables
communication to a device. The adapter can communicate to the I/O device over this connection by
using either the SCSI command set or the Advanced Technology Attachment (ATA) and Advanced
Technology Attachment Packet Interface (ATAPI) command set depending on the device type.
ASAS expander enables connections between an adapter port and multiple I/O device ports by routing
connections between the expander ports. Only a single connection through an expander can exist at a
time. Using expanders creates more nodes in the path from the adapter to the I/O device. If an I/O
device supports multiple ports, more than one path to the device can exist when there are expander
devices included in the path.
ASAS fabric refers to the summation of all paths between all SAS adapter ports and all I/O device ports
in the SAS subsystem including cables, enclosures, and expanders.
SAS subsystem overview
This overview of the SAS subsystem provides the features and locations for the 17M/MB, 17M/MC,
17M/MD, 79M/HB, 79M/HC, or 79M/HD system.
Use this information in conjunction 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 specifically trained on the system unit and subsystem being serviced.
Feature locations
Review the supported SAS features and their system locations.
1

Table 1. SAS subsystem parts
Diagram
location Part name Feature code (FC)
Customer card identification
numbers (CCINs)
Physical
location
codes
A 175 MB Cache RAID –
Dual IOA enablement
card
5662 Card CCIN 2BC2
Note: If FC 5662 is installed, the
embedded SAS adapters report
CCIN 57CF and operate as dual
RAID adapters with write cache
capability.
P2-C9-C1
B Cache battery packs P2-C9-C1-E1
and
P2-C9-C1-E2
C Disk bays (6 SFF drive
disk bays)
P2-C9-C1-D1
through
P2-C9-C1-D6
D Main SAS subsystem card
with two embedded SAS
adapters
Card CCIN 2BBE
Notes:
vIf FC 5662 is not installed, the
embedded SAS adapters report
CCIN 57C7 and operate as two
independent adapters.
vIf FC 5662 is installed, the
embedded SAS adapters report
CCIN 57CF and operate as dual
RAID adapters with write cache
capability.
P2-C9
Figure 1. SAS subsystem overview
2SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

Table 1. SAS subsystem parts (continued)
Diagram
location Part name Feature code (FC)
Customer card identification
numbers (CCINs)
Physical
location
codes
E Optional internal SAS
cables:
vThree-way split disk or
media backplane
configuration (cable FC
1815)
vRAID configuration
with external drives
connected (cable FC
1819)
1815 or 1819
Notes:
v1815 when FC 5662 is
not installed 1
v1819 when FC 5662 is
installed 1
P2-T2
Optional rack-mounted
media drawer with SAS
tape and DVD bays
5720
Notes:
vUses SAS PCIX 2.0
Controller (FC 5900
or 5912) with I/O
drawer (FC 5797,
5798, or 5791)
vUses SAS Dual-x4
Controller (FC 5901)
with I/O drawer (FC
5803)
P2-C9-D7
1For detailed configuration information, see “SAS storage configurations” on page 4.
Feature details
SAS RAID adapters
The SAS RAID adapters have the following features:
vPCI Express (PCIe) system interface
vPhysical link (phy) speed of 3 Gbps SAS supporting transfer rates of 300 MB per second
vOptimized for SAS disk configurations that use dual paths through dual expanders for
redundancy and reliability
vAdapter managed path redundancy and path switching for multiported SAS devices
vEmbedded PowerPC RISC processor, hardware XOR DMA Engine, and hardware Finite Field
Multiplier (FFM) DMA Engine (for Redundant Array of Independent Disks (RAID) 6)
vSupport for RAID 0 and 10 disk arrays
vAdditional features when the 175 MB Cache RAID – Dual IOA enablement card is installed:
– Adapters support nonvolatile write cache
– Support for RAID 5 and 6 disk arrays
– Adapters configured in dual storage IOA or high availability (HA) RAID mode for best
reliability and availability
vRAID disk arrays supported as a boot device
vAdvanced RAID features:
– Hot spares for RAID 5, 6, and 10 disk arrays
– Ability to increase the capacity of an existing RAID 5 or 6 disk array by adding disks
– Background parity checking
– Background data scrubbing
SAS subsystem 3

– 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/write disk support for transaction workloads
175 MB cache RAID – Dual IOA enablement card
This feature is used to enable write cache on the two embedded SAS RAID adapters of the disk
or media backplane by providing the necessary rechargeable batteries for memory backup. It also
enables the two embedded SAS RAID adapters to work as dual storage IOAs, that is, high
availability (HA) RAID mode. This feature plugs in to the disk or media backplane and enables a
175 MB write cache on each of the two embedded RAID adapters by providing two rechargeable
batteries with associated charger circuitry. The write cache can provide additional I/O
performance for attached disk or solid-state drives, particularly for RAID 5 and RAID 6. The
write cache contents are mirrored for redundancy between the two RAID adapters resulting in an
effective write cache size of 175 MB. The batteries provide power to maintain both copies of
write-cache information in the event power is lost.
Related information:
Serial-attached SCSI cable planning
SAS storage configurations
Several SAS subsystem configurations are supported on the 17M/MB, 17M/MC, 17M/MD, 79M/HB,
79M/HC, or 79M/HD systems.
The configuration you use depends on the combination of SAS features that you have installed on your
system. The following table provides an overview of the features and related configurations.
Table 2. SAS subsystem configurations
SAS
subsystem
configuration
175 MB Cache
RAID - Dual
IOA
enablement
card (FC 5662)
External SAS
components SAS port cables SAS cables Limitations
Two-way split
backplane
No
Note: The two
embedded SAS
adapters report
as CCIN 57C7.
None None Not applicable vis not supported.
vConnecting to an
external disk
enclosure is not
supported.
vEach set of three
drives can be
HDDs or SSDs.
Three-way
split
backplane
No
Note: The two
embedded SAS
adapters report
as CCIN 57C7.
Dual-x4 SAS
adapter (FC 5901:
CCIN 57B3)
Internal SAS port
(FC 1815): SAS
cable for
three-way split
backplane
AI cable (FC 3679):
Adapter to internal
drive 1 meter
vis not supported.
vAn I/O adapter
can be located in
another enclosure
of the system.
vEach set of two
drives can be
HDDs or SSDs.
4SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

Table 2. SAS subsystem configurations (continued)
SAS
subsystem
configuration
175 MB Cache
RAID - Dual
IOA
enablement
card (FC 5662)
External SAS
components SAS port cables SAS cables Limitations
Dual storage
IOA
configuration
using internal
disk drives
Yes
Note: The
internal dual
RAID IOA
adapters report
as CCIN 57CF.
None None Not applicable vInternal cable (FC
1815) cannot be
used with the
dual storage IOA
or high
availability (HA)
RAID
configuration.
vThe six drives
can be HDDs or
SSDs.
Dual storage
IOA
configuration
using internal
disk drives
and external
disk enclosure
Yes
Note: The
internal dual
RAID IOA
adapters report
as CCIN 57CF.
Requires an
external disk
enclosure (FC
5886 or FC 5887)
Internal SAS port
(FC 1819): SAS
cable assembly
for connecting to
an external SAS
drive enclosure
vYI cable (FC 3686):
System to SAS disk
enclosure, Single
adapter with Dual
path 1.5 meter
vYI cable (FC 3687):
System to SAS disk
enclosure, Single
adapter with Dual
path 3 meter
Only HDDs are
supported.
vEach node in a system can have a different SAS subsystem configuration.
vUsing the SAS drive assembly on nodes 3 and 4 is optional.
Related concepts:
“SAS subsystem service considerations” on page 12
There are several considerations to review before servicing features within the SAS subsystem for the
17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD system.
“Service considerations for the internal SAS cable for a three-way split backplane” on page 12
To prevent data loss, follow proper procedures before replacing the internal SAS cable for a three-way
split backplane.
“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.
Related information:
Serial-attached SCSI cable planning
175MB Cache RAID - Dual IOA Enablement Card (FC 5662)
SAS subsystem configuration that uses a two-way split backplane
This topic provides rules and examples of a configuration that uses a two-way split backplane.
The following rules apply to this configuration:
SAS subsystem 5

vEach 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.
vThe SAS adapters can be assigned to separate partitions for boot devices.
vThis configuration supports disks without RAID (referred to as JBOD) or RAID drives. However, RAID
drives are limited to three drives and no write cache.
vRAID 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.
vSolid-state drives (SSDs) and hard disk drives (HDDs) can be used, but they can never be mixed in the
same disk enclosure.
vSSD 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 vThe SAS adapter connects to disk drive D1, D2, and
D3.
vPhysical connections to the SAS cable are disabled. If
the external SAS port is installed, it is not functional.
vThe SAS adapter reports CCIN 57C7.
Embedded SAS adapter B vThe SAS adapter connects to disk drive D4, D5, and
D6.
vPhysical connections to the SAS cable are disabled. If
the external SAS port is installed, it is not functional.
vThe 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
6SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD

vA three-way split backplane uses three sets of two drives and cannot function in dual storage I/O
adapter (IOA) or high availability (HA) RAID mode. One SAS adapter connects to D1 and D4. The
other SAS adapter connects to D2 and D5. An external SAS adapter connects to D3 and D6.
vThe SAS adapters can be assigned to separate partitions for boot devices.
vThis configuration supports disks without RAID (referred to as JBOD) or RAID drives. However, RAID
drives are limited to two drives and no write cache.
vRAID 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 drive is not allowed.
vSolid-state drives (SSDs) and hard disk drives (HDDs) can never be mixed in the same disk enclosure.
vSSD and HDD can both be present in a split backplane if each side of the split backplane has only SSD
or HDD.
Example: Three-way split backplane
This example shows a three-way split backplane configuration. Each embedded SAS adapter controls two
disk drives, and the SAS adapter that is connected to the internal cable controls two disk drives.
Figure 3. Disk bays controlled by each embedded SAS adapter in a three-way split backplane
SAS subsystem 7

The following table lists the details of the three-way split backplane configuration.
Table 4. Configuration details
Embedded SAS adapter Configuration details
Embedded SAS adapter A vThe SAS adapter connects to disk drive D1 and D4.
vThe SAS adapter reports CCIN 57C7.
Embedded SAS adapter B vThe SAS adapter connects to disk drive D2 and D5.
vThe SAS adapter reports CCIN 57C7.
SAS adapter (FC 5901) vThe physical connections to the internal SAS cable are
enabled. The SAS adapter that is connected to this
cable connects to disk drive D3 and D6.
vThe SAS adapter reports CCIN 57B3.
SAS subsystem configuration that uses a dual storage IOA with
internal drives
This configuration uses dual storage I/O adapter (IOA) or high availability (HA) RAID mode with
internal disk drives.
This configuration increases availability by using dual storage IOA or high availability (HA) to connect
multiple adapters to a common set of internal disk drives. It also increases the performance of RAID
arrays. The following rules apply to this configuration:
vThis configuration uses the 175 MB Cache RAID – Dual IOA enablement card.
vUsing the dual IOA enablement card, the two embedded adapters can connect to each other and all six
disk drives.
vThe disk drives are required to be in RAID arrays.
Figure 4. Physical connection to internal SAS adapter
8SAS subsystem for the 17M/MB, 17M/MC, 17M/MD, 79M/HB, 79M/HC, or 79M/HD