How to translate the EMC CLARiiON failover modes using “vxdmpadm listenclosure all”

Description

Failover mode 1        A/P-F      Explicit trespass    (usually for PowerPath(PP) )
Failover mode 2        A/P            Implicit failover      (usually for DMP, so PP may not see disks)
Failover mode 4        ALUA                                      Support introduced in 5.0 MP3 RP1

Failover mode 4 is supported with Veritas Volume Manager (VxVM) 5.0MP3RP1 and EMC CLARiiON Flare code 26.

Since FLARE code rev. 26 EMC implemented ALUA (Asymmetric Logical Unit Access), which is basically actice/active I/O handling across both service processors (SP).

ALUA characterizes the arrays in a way that it supports simultaneous I/O on all paths, but seeks the most optimized path for the I/O transmission rate as defined by SPC3.

This setting negates the offline messages seen in /var/adm/messages and <drive type unknown> error under format. Like mode one, trespasses will not occur if this setting is employed

5.0MP3

# vxddladm listsupport libname=libvxCLARiiON.so
ATTR_NAME            ATTR_VALUE
===========================================================================================
LIBNAME              libvxCLARiiON.so 
VID                  DGC
PID                  CLARiiON
ARRAY_TYPE           CLR-A/P, CLR-A/PF
ARRAY_NAME           EMC_CLARiiON

ALUA support listed for the EMC CLARiiON array only with 5.0 MP3 RP1.

5.0MP3RP1

# vxddladm listsupport libname=libvxCLARiiON.so
ATTR_NAME            ATTR_VALUE
=================================================================================================
LIBNAME              libvxCLARiiON.so
VID                  DGC
PID                  All
ARRAY_TYPE           CLR-A/P, CLR-A/PF, ALUA
ARRAY_NAME           EMC_CLARiiON

Note:   VxVM 5.0 MP3 introduces the "libvxpp.so" ASL library which handles the TPD claiming mechanism for PowerPath controlled LUNS.

5.0 MP3 EMC CLARiiON examples

Failovermode=2 (implicit)

# vxdmpadm listenclosure all
ENCLR_NAME           ENCLR_TYPE        ENCLR_SNO               STATUS      ARRAY_TYPE    LUN_COUNT
===================================================================================
emc_clariion0      EMC_CLARiiON    CK200053300424        CONNECTED     CLR-A/P      4
ams_wms0           AMS_WMS         75050205              CONNECTED     A/A-A        6
disk               Disk            DISKS                 CONNECTED     Disk         2

Failovermode =1 (explicit)

# vxdmpadm listenclosure all
ENCLR_NAME           ENCLR_TYPE        ENCLR_SNO               STATUS      ARRAY_TYPE    LUN_COUNT
===================================================================================
emc_clariion0      EMC_CLARiiON    CK200053300424        CONNECTED     CLR-A/PF     4
ams_wms0           AMS_WMS         75050205              CONNECTED     A/A-A        6
disk               Disk            DISKS                 CONNECTED     Disk         2

PowerPath =TPD (Third Party Dirver)

# vxdmpadm listenclosure all
ENCLR_NAME           ENCLR_TYPE        ENCLR_SNO               STATUS      ARRAY_TYPE    LUN_COUNT
===================================================================================
ams_wms0           AMS_WMS         75050205               CONNECTED     A/A-A        6
disk               Disk            DISKS                 CONNECTED     Disk         2
pp_emc_clariion0   PP_EMC_CLARiiON CK200053300424       CONNECTED     A/A          4

CLR-A/P = Failover Mode 2       CLR-A/PF   = Failover Mode 1       A/A   = TPD MODE

How to determine the current “failovermode” setting for a storagegroup

Details surrounding an EMC CLARiiON array can be obtained using the navicli command line interface (Navisphere CLI)

 
# pwd
/opt/Navisphere/bin

# navicli -h <ip-address-for-SP> port -list -failovermode -gname <storage-group-name>

 
Sample output

# navicli -h <ip-address-for-SP> port -list -failovermode -gname rdgv240sol13+14 | egrep 'Server Name| SP Port ID|Failover‘

Server Name:              rdgv240sol13
    SP Port ID:              0
    Failover mode:          1
    SP Port ID:             0
    Failover mode:          1
    SP Port ID:             1
    Failover mode:          1
    SP Port ID:             1
    Failover mode:          1
Server Name:              rdgv240sol14
    SP Port ID:             1
    Failover mode:          2
    SP Port ID:             1
    Failover mode:          2
    SP Port ID:             0
    Failover mode:          2
    SP Port ID:             0
    Failover mode:          2

Note: The EMC CLARiiON storage presented to server "rdgv240sol13" has Failover Mode "1" set, whist server "rdgv240sol14" has Failover Mode "2".