Target Port Group (TPG) IDs Change in 'mpathadm show lu <device>' Command after Sun Storage 2500/6000 Array Reboots

Asset ID:	1-72-1445145.1
Update Date:	2017-05-12
Keywords:

Solution Type Problem Resolution Sure

Solution 1445145.1 : Target Port Group (TPG) IDs Change in 'mpathadm show lu ' Command after Sun Storage 2500/6000 Array Reboots

Applies to:

Solaris SPARC Operating System - Version 10 3/05 HW2 and later
Sun Storage 2510 Array - Version Not Applicable and later
Sun Storage 6780 Array - Version Not Applicable and later
Sun Storage 2530 Array - Version Not Applicable and later
Sun Storage 2530-M2 Array - Version Not Applicable and later
Information in this document applies to any platform.

Symptoms

It is observed that Target Port Group (TPG) ID values, reported in mpathadm show lu <device> output under the "Target Port Groups" section, for LUN(s) from Sun Storage 2500(-M2)/6000 series arrays change after the array reboots. The TPG IDs are swapped after reboot for the respective target ports and also the order in which the TPG displayed, are swapped.

This issue occurs in all instances of Solaris 9/10 connected to Sun Storage 2500(-M2)/6000 series arrays.
However there is a difference in Solaris 11 environment:

This symptom can be seen in a Solaris 11 host connected to Sun Storage 2500(-M2)/6000 series arrays running firmware lower than 07.84.xx.xx,
TPG IDs remain intact if a Solaris 11 host is connected to Sun Storage 2500(-M2)/6000 series arrays running firmware 07.84.xx.xx or higher.

Before reboot:

Target port 202400a0b838900b has TPG id 2
Target port 202500a0b838900b has TPG id 4

# mpathadm show lu /dev/rdsk/c5t600A0B800038A3F3000005944>
Logical Unit: /dev/rdsk/c5t600A0B800038A3F3000005944BA8990Fd0s2
        mpath-support: libmpscsi_vhci.so
        Vendor: SUN
        Product: LCSM100_F
        Revision: 0670
        Name Type: unknown type
        Name: 600a0b800038a3f3000005944ba8990f
        Asymmetric: yes
        Current Load Balance: round-robin
        Logical Unit Group ID: NA
        Auto Failback: on
        Auto Probing: NA

        Paths:
                Initiator Port Name: 2100001b32096c36
                Target Port Name: 202400a0b838900b
                Override Path: NA
                Path State: OK
                Disabled: no

                Initiator Port Name: 2101001b32296c36
                Target Port Name: 202500a0b838900b
                Override Path: NA
                Path State: OK
                Disabled: no

        Target Port Groups:
                ID: 2
                Explicit Failover: yes
                Access State: standby
                Target Ports:
                        Name: 202400a0b838900b
                        Relative ID: 0

                ID: 4
                Explicit Failover: yes
                Access State: active
                Target Ports:
                        Name: 202500a0b838900b
                        Relative ID: 0

After reboot:

Target port 202400a0b838900b has TPG id 4
Target port 202500a0b838900b has TPG id 2

# mpathadm show lu /dev/rdsk/c5t600A0B800038A3F3000005944>
Logical Unit: /dev/rdsk/c5t600A0B800038A3F3000005944BA8990Fd0s2
        mpath-support: libmpscsi_vhci.so
        Vendor: SUN
        Product: LCSM100_F
        Revision: 0670
        Name Type: unknown type
        Name: 600a0b800038a3f3000005944ba8990f
        Asymmetric: yes
        Current Load Balance: round-robin
        Logical Unit Group ID: NA
        Auto Failback: on
        Auto Probing: NA

        Paths:
                Initiator Port Name: 2101001b32296c36
                Target Port Name: 202500a0b838900b
                Override Path: NA
                Path State: OK
                Disabled: no

                Initiator Port Name: 2100001b32096c36
                Target Port Name: 202400a0b838900b
                Override Path: NA
                Path State: OK
                Disabled: no

        Target Port Groups:
                ID: 2
                Explicit Failover: yes
                Access State: active
                Target Ports:
                        Name: 202500a0b838900b
                        Relative ID: 0

                ID: 4
                Explicit Failover: yes
                Access State: standby
                Target Ports:
                        Name: 202400a0b838900b
                        Relative ID: 0

Cause

"Target Port Groups" section in mpathadm output represents Path details for LUNs mapped from arrays which implements TPGS/ALUA supported host type.

Note: TPGS stands for Target Port Group Support and ALUA stands for Asymmetric Logical Unit Access. Refer "Target Port Group Support (TPGS) in the Solaris OS" for more details.

The Sun Storage 2500(-M2)/6000 series arrays with firmware lower than 07.84.xx.xx do not support TPGS/ALUA method host-types for Solaris environment. "Solaris with MPxIO" and "Solaris with DMP" are the only host types available for Solaris environment, and both of these host types implement different failover methods, and not TPGS.

With firmware 07.84.xx.xx, TPGS/ALUA support is included only for Solaris 11.

Solution

The Sun Storage 2500(-M2)/6000 series arrays with firmware lower than 07.84.xx.xx do not support TPGS/ALUA method of failover for Solaris environment (except Solaris 11 as noted above), and hence TPG IDs under "Target Port Groups" section may not be proper and so the number is obviously not persistent across reboots. Note that this will not cause any access issue while using the LUN(s) from host(s) perspective.

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