Hi All,

SPC4r11 added the “offline” state as the secondary target port asymmetric access state. I would like to clarify how the “secondary target port groups” can be reported to an application client with an example configuration.

Let’s assume I have a storage array with two controllers. Each controller has two target ports. I will number the four target ports A1, A2, B1 and B2 respectively. I have A1 and A2 in the primary target port group 1 and B1 and B2 in the primary target port group 2.

The target ports A2 and B2 are not plugged into the SAN network switch initially. Therefore, the A2 and B2 are in “offline” state.

In the returning “REPORT TARGET PORT GROUPS parameter data”, I have two options for reporting the secondary target port groups”.

Option one: report 4 target port group descriptors

            Target port group descriptor 1 – primary target port group 1 – ports A1 and A2

            Target port group descriptor 2 – primary target port group 2 – ports B1 and B2

Target port group descriptor 3 – the first secondary target port group - port A2

Target port group descriptor 4 – the second secondary target port group - port B2

Option two: report 3 target port group descriptors

            Target port group descriptor 1 – primary target port group 1 – ports A1 and A2

            Target port group descriptor 2 – primary target port group 2 – ports B1 and B2

Target port group descriptor 3 – the secondary target port group - ports A2 and B2

The SPC4r11 specifies the “TARGET PORT GROUP identifier” in Table 185 can be correlated with the “TARGET PORT GROUP identifier” returned from “Device Identification VPD page (VPD 0x83 – designator type 5h)”. But the SPC4 doesn’t mention what the TARGET PORT GROUP identifier” in Table 185 should be for a secondary target port group. Especially, for the option two, the secondary target port group has two ports from different primary target port groups. Should the application client ignore “TARGET PORT GROUP identifier” of secondary target port group in Table 185?

After some time, the target ports A2 and B2 are plugged to the SAN network switch. At that time, the “REPORT TARGET PORT GROUPS parameter data” will return 2 target port group descriptors - primary target port group 1 and primary target port group 2.

Please correct me if I am wrongly interpreting the SPC4.

Thanks,

Yanling Qi

Yanling Qi

Engenio Storage Group - LSI Logic

512-794-3713 (Office)

512-794-3702 (Fax)

yanling.qi@lsi.com