Report Target ports in the secondary target port group (TPGS related)

Qi, Yanling Yanling.Qi at lsi.com
Fri Jun 1 08:45:06 PDT 2007


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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 at lsi.com



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