Solaris MPxIO Support of EMC VPLEX OPM (Doc ID 2238077.1)

Last updated on MARCH 02, 2017

Applies to:

Solaris Operating System - Version 10 3/05 and later
Information in this document applies to any platform.

Symptoms

On Solaris 10 the EMC VPLEX OPM device was enumerated / recognized by MPxIO as AA device (which is the default on VPLEX), this is wrong, it should be recognized as an ALUA device.

On S11.3 system the device was not enumerated by MPxIO at all, i.e. multiple paths were reported as a separate devices, this is wrong too.

Solaris 10 example:

 

 


EMC's description of their ALUA implementation:

" We are implementing standard SCSI-3 compliant Implicit ALUA only
(Trespass/STPG not supported). It configures ALUA support on a per-initiator
base instead of per-LU, so it can lead to the TPGS value in VPD 0x83 changing
during I/O , a UA (Unit Attention) will be raised for "Inquiry Data Changed" in that event.
VPLEX may change the TPGS bits during I/O and then raise the "Inquiry Data Changed" UA
to indicate to the host that it should perform INQUIRY again to get the new information.

The VPLEX OPM feature (ALUA) is configurable on a per-initiator basis in the
VPLEX CLI, so when the customer enables it for a host¿s initiators, the TPGS
bits are changed in any INQUIRY response for any LU that comes through those
specific initiators and a UA is raised on the appropriate LUs to indicate
this change. Any VPLEX LU accessed by those initiators will be presented as
an ALUA LU and will respond to RTPG with a list of TPGs and their respective
Access States.

STPG stands for "Set Target Port Groups" which is the SCSI command (service
action of Maintenance In) for Explicit ALUA. This allows the host to set the
TPGs Access States instead of the array. Since VPLEX does not support
Explicit ALUA, only Implicit ALUA, we do not support the STPG command and
will raise a check condition if it is sent.

Only the RTPG command "Report Target Port Groups" is supported.

VPLEX can present its devices as either A/A or ALUA,
but they are usually mutually exclusive in the eyes of the host.

Actually this OPM/ALUA is now disabled by default at VPLEX 5.5 release.
And when disabled everything looks normal : Asymmetric=yes "

 

 

Cause

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