PowerPath: AIX: Shared device settings

Environment:

PowerPath for AIX

PowerPath

PowerPath Multipathing

Description

 

Incorrect reserve policy settings can lead to unpredictable results including data loss.

Issue 1:

 

INQ output has strange data for Symmetrix devices:

/dev/rhdiskpower2  000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk4      000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk11      000292605010  0097B    60060480000292605010533030393742<---notice 6006048 as leading numbers. This is INQ using old default for DMX devices.

/dev/rhdisk18      000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk25      000292605010  0097B    60000970000292605010533030393742

Should always read as:

/dev/rhdiskpower2  000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk4      000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk11      000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk18      000292605010  0097B    60000970000292605010533030393742

/dev/rhdisk25      000292605010  0097B    60000970000292605010533030393742

Issue 2:

 

AIX 'powermt config' command gives error '0514-034 The following attributes do not have valid values'

Affected hdiskpower devices show up as defined in the lsdev -Cc disk (although they may appear normal in the powermt display dev=all).

Issue 3:

 

hdisk placed in pseudo name or pseudo name is missing or is unknown.

Pseudo name=hdisk3

VPLEX ID=CKM00135101X72 

Logical device ID=60001440000000107035135C39FFB9CC

state=alive; policy=ADaptive; queued-IOs=0

==============================================================================

--------------- Host ---------------  - Stor -  -- I/O Path --  -- Stats ---

###  HW Path              I/O Paths    Interf.  Mode    State  Q-IOs Errors

==============================================================================

  1 fscsi1                hdisk15    CL2-01  active  alive      0      0

Pseudo name=UNKNOWN

VPLEX ID=CKM00135101X72 

Logical device ID=60001440000000107035135C39FFBD4D

state=alive; policy=ADaptive; queued-IOs=0

==============================================================================

--------------- Host ---------------  - Stor -  -- I/O Path --  -- Stats ---

###  HW Path              I/O Paths    Interf.  Mode    State  Q-IOs Errors

==============================================================================

  1 fscsi1                hdisk19    CL2-01  active  alive      0      0

  0 fscsi0                hdisk7      CL2-04  active  alive      0      0

Pseudo name=hdiskpower11

VPLEX ID=CKM00135101X72 

Logical device ID=60001440000000107035135C39FFBD7D

state=alive; policy=ADaptive; queued-IOs=0

==============================================================================

--------------- Host ---------------  - Stor -  -- I/O Path --  -- Stats ---

###  HW Path              I/O Paths    Interf.  Mode    State  Q-IOs Errors

==============================================================================

  1 fscsi1                UNKNOWN CL2-01  active  alive      0      0

  0 fscsi0                hdisk8      CL2-04  active  alive      0      0

Issue 4:

BLANK, Failed, '----' capacity in INQ output

--------------------------------------------------------------------------------------------

DEVICE            :VEND    :PROD            :REV  :SER NUM    :CAP(kb)      :Bus :Tid :Lun

--------------------------------------------------------------------------------------------

/dev/rhdiskpower0 :EMC    :SYMMETRIX      :5876  :1000979000 :    ------    :  0:  0:  9<---dashes for capacity

/dev/rhdiskpower1 :EMC    :SYMMETRIX      :5876  :100097a000 :              :  0:  0:  a<---Capacity blank

/dev/rhdisk2      :EMC    :SYMMETRIX      :5876  :1000979000 :    FAILED  :  0:  0:  2<---Capacity failed

/dev/rhdisk3      :EMC    :SYMMETRIX      :5876  :100097a000 :    67109760:  0:  0:  3

/dev/rhdisk9      :EMC    :SYMMETRIX      :5876  :1000979000 :    67109760:  0:  0:  9

/dev/rhdisk10    :EMC    :SYMMETRIX      :5876  :100097a000 :    67109760:  0:  0:  a

/dev/rhdisk16    :EMC    :SYMMETRIX      :5876  :1000979000 :    67109760:  0:  0:  2

/dev/rhdisk17    :EMC    :SYMMETRIX      :5876  :100097a000 :    67109760:  0:  0:  3

/dev/rhdisk23    :EMC    :SYMMETRIX      :5876  :1000979000 :    67109760:  0:  0:  9

/dev/rhdisk24    :EMC    :SYMMETRIX      :5876  :100097a000 :    67109760:  0:  0:  a

Issue 5:

Some devices become defined at reboot:

hdisk18  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk19  Defined  0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk20  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk21  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk28  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk29  Defined  0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk30  Defined  0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk31  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk32  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk33  Defined  0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk34  Available 0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk43  Defined  0R-08-02    EMC CLARiiON FCP RAID 5 Disk

hdisk44  Defined  0R-08-02    EMC CLARiiON FCP RAID 5 Disk

Issue 6:

 

PVID does not move to pseudo device.

hdiskpower0    00f8deff0306eeb2                    gpfs1nsd                   

hdiskpower1    00f8deff030c5641                    gpfs2nsd                   

hdiskpower2    00f8deff0311776a                    None

hdiskpower3  None                                        None

hdiskpower4  None                                        None                       

hdisk25        00f8deff0306eeb2                    gpfs1nsd                   

hdisk26        00f8deff030c5641                    gpfs2nsd                   

hdisk27        00f8deff0311776a                    None                       

hdisk28        00f8deff0306eeb2                    gpfs1nsd                   

hdisk29        00f8deff030c5641                    gpfs2nsd                   

hdisk30        00f8deff0311776a                    None                       

hdisk31        00f8deff0306eeb2                    gpfs1nsd                   

hdisk32        00f8deff030c5641                    gpfs2nsd                   

hdisk33        00f8deff0311776a                    None

Issue 7:

Reservation conflicts

---------------------------------------------------------------------------

LABEL:        SC_DISK_ERR10

IDENTIFIER:    65DE6DE3

Date/Time:      Mon Dec 14 10:46:59 2015

Sequence Number: 145850

Machine Id:      00C15EE74C00

Node Id:        opccmodtest

Class:          S

Type:            PERM

WPAR:            Global

Resource Name:  hdisk3

Description

REQUESTED OPERATION CANNOT BE PERFORMED

Probable Causes

DASD DEVICE

User Causes

RESOURCE NOT AVAILABLE

UNAUTHORIZED ACCESS ATTEMPTED

    Recommended Actions

    FOR REMOVABLE MEDIA, CHANGE MEDIA AND RETRY

    PERFORM PROBLEM DETERMINATION PROCEDURES

Failure Causes

MEDIA

DISK DRIVE

    Recommended Actions

    FOR REMOVABLE MEDIA, CHANGE MEDIA AND RETRY

    PERFORM PROBLEM DETERMINATION PROCEDURES

Detail Data

PATH ID

          0

SENSE DATA

0600 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0118 0000 0000 0000

0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000

0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000

0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000

0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000

0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000

0000 0000 0000 0003 1307 0000 0300 0000 0000 0000 0000 0000 0000 0000 0083 0000

0418 003D 001A

Duplicates

Number of duplicates

          11

Time of first duplicate

Mon Dec 14 10:46:48 2015

Time of last duplicate

Mon Dec 14 10:46:59 2015

---------------------------------------------------------------------------

 

This is caused because SCSI reservations, either on host or another host, holds path causing the path to become defined from an available state.

 

Resolution:

 

For all issues and symptoms, make sure all paths and pseudo devices have the same reserve policies by checking

lsattr -El hdisk(#)/hdiskpower(#)

 

# chdev -l hdiskx -a reserve_lock=no -P

Command to use with PP5.3 and earlier.

# chdev -l hdiskx -a reserve_policy=no_reserve -P

Command for PP 5.5 +

Reboot.

DO NOT skip this step because  -P causes change to happen at reboot.

# lsattr -El hdisk(#)/hdiskpower(#)

To verify policies match.

# powermt config

# powermt display dev=hdiskpower(#) that was changed to verify that the paths are now active.

# powermt save if everything is correct.

 

For an alternate solution and detailed step by step resolution please refer to EMC Support Solution https://support.emc.com/kb/464279

 

 

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