Planning for serial-attached SCSI cables

Serial-attached SCSI (SAS) cables provide serial communication for transfer of data for directly attached devices, such as hard disk drives, solid-state drives, and CD-ROM drives.

SAS cable overview

Serial-attached SCSI (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 that are used as two differential signal pairs. One differential signal transmits in one direction while the other differential signal transmits in the opposite direction. Data might be transmitted in both directions simultaneously. SAS physical links are contained in ports. A port contains one or more SAS physical links. A port is a wide port if there are more than one SAS physical link in the port. Wide ports are designed to enhance performance and provide redundancy in case an individual SAS physical link fail.

There are two types of SAS connectors, mini SAS and mini SAS high density (HD). High-density cables are typically needed to support 6 Gb/s SAS.

Each SAS cable contains four SAS physical links that are typically organized into either a single 4x SAS port or two 2x SAS ports. Each end of the cable uses a mini SAS or mini SAS HD 4x connector. Review the following design and installation criteria before you install SAS cables:

  • Only specific cabling configurations are supported. Many configurations can be constructed that are not supported and will either not function correctly or generates errors. See SAS cabling configurations for figures of the supported cabling configurations.
  • Each mini-SAS 4x connector is keyed to help prevent cabling an unsupported configuration.
  • HD SAS cables have a key that prevents the cable retention from latching if the cable is oriented incorrectly. HD SAS cables will slide in easily and latch correctly if they are inserted with the blue release tab on the right side of the card connector.
  • Each cable end has a label that graphically describes the correct component port to which it is connected, such as:
    • SAS adapter
    • Expansion drawer
    • System external SAS port
    • Internal SAS disk slots connection.
  • Cable routing is important. For example, YO, YI, and X cables must be routed along the right side of the rack frame (as viewed from the rear) when connecting to a disk expansion drawer. Additionally, X cables must be attached to the same numbered port on both SAS adapters to which it connects.
  • When a choice of cable lengths is available, select the shortest cable that provides the needed connectivity.
  • Always use care when you insert or remove a cable. The cable should slide easily into the connector. Forcing a cable into a connector can cause damage to the cable or connector.
  • The X cables are only supported on all SAS PCI (RAID) adapters and only when RAID is enabled.
  • New SAS cables with mini-SAS HD narrow connectors are required for any PCIe3 SAS adapter connection. These cables are also compatible with earlier PCIe2 SAS adapters.
  • Not all cabling configurations are supported when you use solid-state drives (SSD). See Installing and configuring Solid State Drives for more information.

Supported SAS cable information

The following table contains a list of the supported serial-attached SCSI (SAS) cable types and their designed usage.

Table 1. Functions for supported SAS cables
Cable type Function
AA cable This cable is used to connect between the top ports on two PCIe2 tri-port SAS adapters or to connect the top one or two ports on two PCIe3 caching SAS RAID adapters.
AI cable This cable is used to connect from a SAS adapter to internal SAS disk slots that uses an FC 3650 or FC 3651 cable card, or by using an FC 3669 to the system external SAS port on your system.
AE cable These cables are used to connect a SAS adapter to a media expansion drawer. These cables can also be used to connect two SAS adapters to a disk expansion drawer in a unique JBOD configuration.
EE cable This cable is used to connect one disk expansion drawer to another in a cascaded configuration. Disk expansion drawers can be cascaded one level deep, and only in certain configurations.
YO cable This cable is used to connect a SAS adapter to a disk expansion drawer. The cable must be routed along the right side of the rack frame (as viewed from the rear) when connecting to a disk expansion drawer.
YI cable This cable is used to connect a system external SAS port to a disk expansion drawer. The cable must be routed along the right side of the rack frame (as viewed from the rear) when connecting to a disk expansion drawer.
X cable This cable is used to connect two SAS adapters to a disk expansion drawer in a RAID configuration. The cable must be routed along the right side of the rack frame (as viewed from the rear) when connecting to a disk expansion drawer.
AE1 cable This 4 m (13.1 ft) SAS cable connects a PCIe3 SAS adapter to a SAS tape drive or DVD I/O enclosure. The AE cable has two connectors, one mini-SAS HD narrow connector and one mini-SAS connector. The mini-SAS HD Narrow connector attaches to a PCIe3 SAS adapter. The mini-SAS connector attaches to a SAS tape drive or DVD enclosure.
YE1 cable This 3 m (9.8 ft) SAS cable connects a PCIe3 SAS adapter to one or two SAS tape drives in an I/O enclosure. The YE1 cable has three connectors, one mini-SAS HD (High Density) narrow connector and two mini-SAS connectors. The Mini-SAS HD Narrow connector attaches to a PCIe3 SAS adapter. Each mini-SAS connector attaches to a different SAS tape drive.
AS cable This 3 m (9.8 ft) SAS cable is used to attach a DCS3700 to PCIe3 LP RAID SAS adapter.

The following table contains specific information about each supported SAS cable for PCIe2 and prior SAS adapters.

Table 2. Supported SAS cables for PCIe2 and prior SAS adapters
Name Length IBM® part number Feature code
SAS 4x AI cable 1 m (3.2 ft) 44V4041 3679
SAS 4x AE cable 3 m (9.8 ft) 44V4163 3684
6 m (19.6 ft) 44V4164 3685
SAS 4x AT cable 0.6 m (1.9 ft) 44V5132 3688
SAS 4x EE cable 1 m (3.2 ft) 44V4147 3652
3 m (9.8 ft) 44V4148 3653
6 m (19.6 ft) 44V4149 3654
HD SAS 4x AT cable 0.6 m (1.9 ft) 74Y6260 3689
HD SAS AA cable 0.6 m (1.9 ft) 00J0094 5918
1.5 m (4.9 ft) 74Y9029 5917
3 m (9.8 ft) 74Y9030 5915
6 m (19.6 ft) 74Y9031 5916
HD SAS EX cable 1.5 m (4.9 ft) 00E5648 5926
3 m (9.8 ft) 74Y9033 3675
6 m (19.6 ft) 74Y9034 3680
HD SAS X cable 3 m (9.8 ft) 74Y9041 3454
6 m (19.6 ft) 74Y9042 3455
10 m (32.8 ft) 74Y9043 3456
15 m (49.2 ft) 74Y9044 3458
HD SAS YO cable 1.5 m (4.9 ft) 74Y9036 3450
3 m (9.8 ft) 74Y9037 3451
6 m (19.6 ft) 74Y9038 3452
10 m (32.8 ft) 74Y9039 3453
15 m (49.2 ft) 74Y9040 3457
SAS AA cable 3 m (9.8 ft) 44V8231 3681

6 m (19.6 ft)

44V8230

3682

SAS YO cable 1.5 m (4.9 ft) 44V4157 3691
3 m (9.8 ft) 44V4158 3692
6 m (19.6 ft) 44V4159 3693
15 m (49.2 ft) 44V4160 3694
SAS YI cable 1.5 m (4.9 ft) 44V4161 3686
3 m (9.8 ft) 44V4162 3687
SAS X cable 3 m (9.8 ft) 44V4154 3661
6 m (19.6 ft) 44V4155 3662
15 m (49.2 ft) 44V4156 3663
Disk backplane to rear bulkhead, cascading. (internal cable)   42R5751 3668
Split disk backplane to rear bulkhead (internal cable)   44V5252 3669
The following table contains specific information about each supported SAS cable feature with narrow HD connectors for PCIe3 SAS adapters.
Table 3. Supported SAS cables for PCIe3 SAS adapters
Name Length IBM part number Feature code

HD SAS AA12 narrow connector cable, SAS adapter to SAS adapter

0.6 m (1.9 ft)

01AF505

ECE0

1.5 m (4.9 ft)

01AF506

ECE2

3 m (9.8 ft)

01AF507

ECE31

4.5 m (14.8 ft) AOC2

78P4917

ECE4

HD SAS X12 narrow connector cable, SAS adapter to storage enclosure

3 m (9.8 ft)

01AF504

ECDJ

4.5 m (14.8 ft) AOC2

78P4918

ECDK

10 m (32.8 ft) AOC2

78P4919

ECDL

HD SAS YO12 narrow connector cable, two SAS adapters to storage enclosure

1.5 m (4.9 ft)

01AF502

ECDT

3 m (9.8 ft)

01AF503

ECDU

4.5 m (14.8 ft) AOC2

78P4920

ECDV

10 m (32.8 ft) AOC2

78P4921

ECDW

HD SAS 4x AT narrow connector cable

0.6 m (1.9 ft)

00E6291

ECBB

HD SAS AA narrow connector cable

0.6 m (1.9 ft)

00E6287

ECC0

1.5 m (4.9 ft)

00E6288

ECC2

3 m (9.8 ft)

00E6289

ECC3

6 m (19.6 ft)

00E6290

ECC4

HD SAS X narrow connector cable

3 m (9.8 ft)

00E6297

ECBJ

6 m (19.6 ft)

00E6298

ECBK

10 m (32.8 ft)

00E6299

ECBL

15 m (49.2 ft)

00E6300

ECBM

HD SAS YO narrow connector cable

1.5 m (4.9 ft)

00E6292

ECBT

3 m (9.8 ft)

00E6293

ECBU

6 m (19.6 ft)

00E6294

ECBV

10 m (32.8 ft)

00E6295

ECBW

15 m (49.2 ft)

00E6296

ECBX

HD SAS AE1 narrow connector cable

4 m (13.1 ft)

46C2900

ECBY/5507

HD SAS YE1 narrow connector cable

3 m (9.8 ft)

46C2902

ECBZ/5509

HD SAS AS narrow connector cable

3 m (9.8 ft)

00FW799

ECC5

  1. Can be used to attach just a bunch of disks (JBOD) storage enclosures to adapters.
  2. Active optical cables (AOC).

The following table contains cable label information. The graphic labels are designed to match the correct component port to which the cable end is to be attached.

Table 4. SAS cable labeling
Name Connects Label
SAS 4x AE cable SAS adapter to a media expansion drawer or two SAS adapters to a disk expansion drawer in a unique JBOD configuration

SAS 4x AE cable (1 m)

SAS 4x AE cable (3 m and 6 m)

SAS 4x AI cable SAS adapter to internal SAS disk slots to the system external SAS port on your system
SAS 4x AI cable (1 m)
SAS 4x EE cable One disk expansion drawer to another disk expansion drawer in a cascaded configuration
SAS 4x EE cable

SAS AA cable

SAS adapter to SAS adapter
SAS AA cable (1 m)

SAS YO cable

SAS adapter to a disk expansion drawer

SAS YO cable (1 m)

SAS YO cable

SAS X cable

Two SAS adapters to a disk expansion drawer in a RAID configuration

SAS X cable (1 m)

SAS X cable

SAS YI cable System external SAS port to a disk expansion drawer

SAS YI cable

SAS YI cable

Cable section lengths

Figure 1. SAS external X cable assembly cable lengths
SAS external X-cable assembly cable lengths
Figure 2. SAS external YO-cable assembly cable lengths
SAS external YO-cable assembly cable lengths
Figure 3. SAS external YI-cable assembly cable lengths
SAS external YI-cable assembly cable lengths

SAS cabling configurations

SAS adapter to 5886 disk expansion drawers

Figure 4, Figure 5, Figure 6, and Figure 7 illustrate connecting a SAS adapter to one, two, three, or four disk expansion drawers. It is also possible to connect three disk expansion drawers by omitting one of the cascaded drawers that are shown in Figure 6. Disk expansion drawers can be cascaded only one level deep.

Figure 4. SAS adapter to a disk expansion drawer
SAS adapter to a disk expansion drawer
Note: The YO cable must be routed along the right side of the rack frame.
Figure 5. SAS adapter to two disk expansion drawers
SAS adapter to two disk expansion drawers
Note: The YO cable must be routed along the right side of the rack frame.
Figure 6. SAS adapter to four disk expansion drawers
SAS adapter to four disk expansion drawers
Note: The YO cable must be routed along the right side of the rack frame.
Figure 7. Tri-port SAS adapter to disk expansion drawers
Tri-port SAS adapter to disk expansion drawers

When attaching only hard disk drives, it is also possible to cascade a second disk expansion drawer off two out of the three drawers for a maximum of five disk expansion drawers per adapter. See Figure 6. Disk expansion drawers can be cascaded only one level deep.

Note: The YO cable must be routed along the right side of the rack frame.

SAS adapter to media expansion drawer

Figure 8 illustrates connecting a SAS adapter to a media expansion drawer. It is also possible to connect a second media expansion drawer to the second port of the SAS adapter.
Figure 8. SAS adapter to a media expansion drawer
SAS adapter to a media expansion drawer

SAS adapter to expansion drawer combinations

Figure 9 illustrates connecting a SAS adapter to both a disk expansion drawer and a media expansion drawer on separate adapter ports. It is also possible to cascade a second disk expansion drawer (see Figure 6).
Figure 9. SAS adapter to both a disk expansion drawer and a media expansion drawer
SAS adapter to both a disk expansion drawer and a media expansion drawer
Note: The YO cable must be routed along the right side of the rack frame.

System external SAS port to disk expansion drawer

Figure 10 illustrates connecting a system external SAS port to a disk expansion drawer. Disk expansion drawers cannot be cascaded.
Figure 10. System external SAS adapter port to a disk expansion drawer
System external SAS adapter port to a disk expansion drawer
Note: The YI cable must be routed along the right side of the rack frame.

SAS adapter to internal SAS disk slots

Figure 11 illustrates connecting a SAS adapter to internal SAS disk slots through the system external SAS port.

Note: Internal cable FC 3669 must be installed to enable this configuration.
Figure 11. SAS adapter to internal SAS disk slots through the system external SAS port
Two SAS adapters to two disk expansion drawers in a RAID configuration
Notes:
  • The second connector on the adapter can be used to attach a disk expansion or media expansion drawer as shown in Figure 4 or Figure 8.
Figure 12. FC5904 or FC5908 adapter attached to disk expansion drawers
FC5904 or FC5908 adapter that is attached to disk expansion drawers
Note:
  • The remaining two connectors on the adapter can be used to attach disk expansion drawers as shown in Figure 7.

Two SAS adapters to 5886 disk expansion drawer multi-initiator high availability (HA) RAID configuration

Figure 13, Figure 14, Figure 15, and Figure 16 illustrate connecting two SAS adapters to one, two, or four disk expansion drawers in a RAID configuration. It is also possible to connect three disk expansion drawers by omitting one of the cascaded drawers that are shown in Figure 15. Disk expansion drawers can be cascaded only one level deep.

Figure 13. Two SAS RAID adapters to a disk expansion drawer in a multi-initiator HA RAID configuration
Two SAS adapters to a disk expansion drawer in a multi-initiator HA RAID configuration
Notes:
  • The X cable must be routed along the right side of the rack frame.
  • The X cable must be attached to the same numbered port on all adapters.
Figure 14. Two SAS RAID adapters to two disk expansion drawers in a multi-initiator HA RAID configuration
Two SAS adapters to two disk expansion drawers in a multi-initiator HA RAID configuration
Notes:
  • The X cable must be routed along the right side of the rack frame.
  • The X cable must be attached to the same numbered port on all adapters.
Figure 15. Two SAS RAID adapters to four disk expansion drawers in a multi-initiator HA RAID configuration
Two SAS adapters to four disk expansion drawers in a multi-initiator HA RAID configuration
Notes:
  • The X cable must be routed along the right side of the rack frame.
  • The X cable must be attached to the same numbered port on all adapters.
Figure 16. Two PCI-X DDR 1.5 GB cache SAS RAID adapters to disk expansion drawers in a multi-initiator HA raid configuration
Two PCI-X DDR 1.5 GB cache SAS RAID adapters to disk expansion drawers in a multi-initiator HA raid configuration

When attaching only hard disk drives, it is also possible to cascade a second disk expansion drawer off two out of the three drawers for a maximum of five disk expansion drawers per adapter. See Figure 6.

Notes:
  • Disk expansion drawers can be cascaded only one level deep.
  • The X cable must be routed along the right side of the rack frame.
  • The X cable must be attached to the same numbered port on all adapters.
  • Any multi-initiator configuration with FC 5904, FC 5906, and FC 5908 adapters require an AA cable for connecting the two adapters with each other.

Two RAID SAS adapters with HD connectors to disk expansion drawer in a multi-initiator high availability (HA) mode

Figure 17, Figure 18, and Figure 19 illustrate connecting two SAS RAID adapters with HD connectors to one, two, or three disk expansion drawers in a multi-initiator HA mode.

Figure 20 illustrates connecting two pair of SAS RAID adapters with HD connectors to one disk expansion drawer in a multi-initiator HA mode.

Figure 17. Two RAID SAS adapters with HD connectors to a disk expansion drawer in a multi-initiator HA mode
Two RAID SAS adapters with HD connectors to a disk expansion drawer in a multi-initiator HA mode
Notes:
  • No cascading allowed for the 5887 storage drawer.
  • The 5887 storage drawer is connected to same numbered port on each adapter.
  • HD AA cable is required.
Figure 18. Two RAID SAS adapters with HD connectors to two disk expansion drawer in a multi-initiator HA mode
Two RAID SAS adapters with HD connectors to two disk expansion drawer in a multi-initiator HA mode.
Notes:
  • No cascading allowed for the 5887 storage drawer.
  • The 5887 storage drawers are connected to same numbered port on each adapter.
  • HD AA cable is required.
Figure 19. Two RAID SAS adapters with HD connectors to three disk expansion drawers in a multi-initiator HA mode
Two RAID SAS adapters with HD connectors to three disk expansion drawers in a multi-initiator HA mode
Note:
  • No cascading allowed for the 5887 storage drawer.
  • The 5887 storage drawers are connected to same numbered port on each adapter.
Figure 20. Two pairs of RAID SAS adapters with HD connectors to a disk expansion drawer – Mode 2 in a multi-initiator HA mode
Two pairs of RAID SAS adapters with HD connectors to a disk expansion drawer – Mode 2 in a multi-initiator HA mode.
Notes:
  • No cascading allowed for the 5887 storage drawer.
  • The 5887 storage drawer is connected to same numbered port on each adapter.
  • HD AA cable is required.

Two SAS adapters to disk expansion drawer - multi-initiator HA JBOD configuration

Figure 21 illustrates connecting two SAS adapters to a disk expansion drawer in a unique JBOD configuration.

Figure 21. Two RAID SAS adapters to a disk expansion drawer in a multi-initiator HA JBOD configuration
Two SAS adapters to a disk expansion drawer in a unique multi-initiator HA JBOD configuration
Note: This configuration is only supported by the AIX® and Linux operating systems with specific SAS adapters and requires special user configuration setup. See SAS RAID configurations for additional information.

Internal disk drive sharing

The following information is for use after the FC 5901 SAS Storage adapter is installed. Install the adapter and then return here. For more information about the PCI adapters topic, see Managing PCI adapters for the 8247-21L, 8247-22L, or 8284-22A or Managing PCI adapters for the 8247-42L, 8286-41A, or 8286-42A.

Please review the tasks in the Before you begin section before you proceed with the following procedure.

This feature allows you to split the internal disks in the system unit enclosure into groups that you can manage separately.

  1. Stop and power off the system. For more information, see Stopping a system or logical partition.
  2. Cable a single system unit enclosure by completing the following steps:
    1. Attach the cable to the SAS port on the rear bulkhead of the system unit enclosure to the top port in the SAS Storage Controller as shown in the following figure.

      Restriction: Internal disk drive sharing is only available when internal cable feature FC 1815 is installed from the DASD backplane to the read bulkhead of the system unit enclosure. Also FC 5662 175 MB cache RAID - dual IOA enablement card must not be installed. The SAS Storage Controller might be in any of the other slots that support it.

    2. Secure any extra cable.
  3. Start the system. For more information, see Starting the system or logical partition.
  4. Verify that the feature is installed and is working. For more information, see Verifying the installed part.

With this function installed, two of the six disks (D3 and D6) in the system enclosure is managed by the SAS storage controller adapter.

Note: The removable media device is always controlled by the separate embedded SAS controller on the system planar. For more information about installing and removing SAS media devices, see Removing and replacing a Slimline media device in the 8247-21L, 8247-22L, 8284-22A, 8286-41A, or 8286-42A.



Last updated: Tue, February 02, 2021