Chapter 7. Sas Address And Physical Location Information - IBM SAS RAID Series Manual

Chapter 7. SAS address and physical location information

Many hardware error logs identify the location of a physical device, such as a SAS disk, using what is
called a unit address.
The resource format is: cceellFF where:
v cc identifies the controller's port to which the device, or device enclosure, is attached.
v ee is the expander's port to which the device is attached. When a device is not connected to a SAS
expander, for example, the device is directly connected, the expander port is set to zero.
Typically, the expander port will be in a range of 00 to 3F hex. A value greater than 3F indicates there are
two expanders (for example, cascaded expanders) between the controller and device. For example, a
device connected through a single expander might show an expander port of 1A, while a device
connected through a cascaded expander might show an expander port of 5A (that is, a value of 40 hex
added to the expander port indicates the presence of a cascaded expander), but in both cases, the device
is connected off port 1A of the expander.
A value of FF indicates the expander port is not known.
v ll is the logical unit number (LUN) of the device.
A value of FF indicates the LUN is not known.
A resource can identify a physical device or it can identify other SAS components. For example:
v FFFFFFFF indicates the identity of the device is not known or indicates a SAS RAID controller.
v ccFFFFFF identifies only a controller's SAS port.
v cceellFF identifies the controller port, expander port, and LUN of an attached device.
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