SAS configuration details

Apply these system configuration details for serial-attached SCSI (SAS) host connections.

SAS connections require a direct attachment from the host to a system. The host and the system cannot be attached via a SAS switch.

To ensure continuity during failover scenarios, directly attach each host to both system canisters. Use a multipathing device driver on the host to provide a redundant connection to mapped volumes.

Subsystem Device Driver Device Specific Module (SDDDSM) is required for SAS MicrosoftWindows hosts. For information about SDDDSM, search for Support Matrix for Subsystem Device Driver at the following site:

www.ibm.com/support/portal/overview

The Multipath Subsystem Device Driver user's guides are at this site:

www-01.ibm.com/support/docview.wss?uid=ssg1S7000303

SAS port speed and mapping

The SAS host ports on Lenovo Storage V series node canisters can operate at 6 Gbps or 12 Gbps. The Lenovo Storage V3700 V2 XP system has two onboard 12 Gbps host attachment SAS ports. Lenovo Storage V3700 V2 XP systems can also support the optional SAS host interface adapter.Lenovo Storage V3700 V2, Lenovo Storage V5030, and Lenovo Storage V5030F systems support 12 Gbps SAS host attachment I/O but must have the optional host interface adapter installed. These models require different cables based on the speeds. If you want to run 12 Gbps SAS, you need to use a 12 Gbps cable.

Attention:

12 Gbps SAS cables have a square design rather than a rectangular design, which makes them easy to insert upside down. You can identify the correct orientation by observing the ridge at the top of the SAS connector and lining it up with the ridge on the node canister. However, this ridge is not enough to prevent the cable from being inserted incorrectly. Take extra care as the orientation of the SAS ports on a connector for a host interface adapter is the opposite of the onboard SAS ports.
If either one of the adapters or the cable is designed for 6 Gbps I/O, the I/O runs at 6 Gbps, regardless of the other components.

Using the management GUI to configure SAS host attachment

To configure SAS host attachment by using the management GUI, first select Hosts > Hosts > Add Hosts and then select SAS for the host connection.

Using the CLI to configure SAS host attachment

To configure SAS host attachment on your system by using the CLI, complete the following steps:

Run the lsportsas command to locate the SAS WWPNs on each operating system.
Run the appropriate operating system command:
- On Linux, run cat /sys/class/sas_phy/phy-*/sas_address|sort|uniq
- On MicrosoftWindows Server, run the sas2flash utility: ./sas2flash -list
Run the lssasportcandidate command to detect the WWPNs associated with the host that is to be added.
Create the host:
```
mkhost -saswwpn wwpn_list
```
The WWPNs are 16-character hexadecimal strings that are separated by colons.