1. Obtain the enclosure name of the array to be changed to A/P:

# vxdmpadm listenclosure all

ENCLR_NAME        ENCLR_TYPE    ENCLR_SNO      STATUS      ARRAY_TYPE
============================================================================
Disk              Disk          DISKS                CONNECTED    Disk
EMC0              EMC            461126              CONNECTED    A/A


2. List the current I/O policy for this enclosure:

# vxdmpadm getattr enclosure EMC0iopolicy

ENCLR_NAME    DEFAULT        CURRENT
============================================
EMC0          MinimumQ       MinimumQ



3.Change the iopolicy to single active:

#vxdmpadm setattr enclosure EMC0iopolicy=singleactive

# vxdmpadm getattr enclosure EMC0iopolicy

ENCLR_NAME    DEFAULT        CURRENT
============================================
EMC0          MinimumQ       Single-Active


4.Verify I/O is only being sent down one path by generating some I/O to the devices in the enclosure:

Example:

# vxprint -ht

v  vol1        -            ENABLED  ACTIVE  204800  SELECT    -        fsgen
pl vol1-01      vol1        ENABLED  ACTIVE   204800  CONCAT    -        RW
sd Disk_8-01    vol1-01      Disk_8  0        204800   0        EMC0_0   ENA

# mount-F vxfs /dev/vx/dsk/testdg/vol1/mnt
# cp -r /usr/mnt

# iostat -xnc2

                 extended device statistics
   r/s    w/s  kr/s   kw/s wait actv wsvc_t asvc_t  %w  %bdevice
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0fd0
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c0t1d0
   0.6  35.1    4.8   58.9  0.0  1.7    0.0  46.5   0  15c0t0d0
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c0t6d0
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d31
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d30
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d29
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d28
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d27
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d26
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d25
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d24
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d23
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d22
   0.0  135.5    0.0  860.8  0.0  0.4    0.0    3.3  0   3c2t50060482CB1B81A2d31
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d30
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d29
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d28
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d27
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d26
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d25
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d24
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d23
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d22
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0bambam:vold(pid656)


                   extended device statistics
   r/s    w/s  kr/s   kw/s wait actv wsvc_t asvc_t  %w  %bdevice
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0fd0
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c0t1d0
   0.0    0.2    0.0    0.4  0.0  0.0    0.0    4.3  0   0c0t0d0
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c0t6d0
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d31
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d30
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d29
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d28
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d27
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d26
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d25
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d24
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d23
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c3t50060482CB1B81A2d22
   0.0  12.0    0.0  90.5  0.0  0.0    0.0    1.2   0   0c2t50060482CB1B81A2d31
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d30
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d29
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d28
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d27
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d26
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d25
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d24
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d23
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0c2t50060482CB1B81A2d22
   0.0    0.0    0.0    0.0  0.0  0.0    0.0    0.0  0   0 bambam:vold(pid656)


5. Explanation of' singleactive' iopolicy

This policy routes I/O down the single active path. This policy can be configured for A/P arrays with one active path per controller, where the other paths are used in case of failover. If configured for A/A arrays, there is no load balancing across the paths, and the alternate paths are only used to provide high availability (HA). If the currently active path fails, I/O is switched to an alternate active path. No further configuration is possible as the single active path is selected by DMP.