Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

This shows that the policy for the enclosure is set to singleactive, which explains
why all the I/O is taking place on one path.
To balance the I/O load across the multiple primary paths, the policy is set to
round-robin as shown here:
# vxdmpadm setattr enclosure ENC0 iopolicy=round-robin
# vxdmpadm getattr enclosure ENC0 iopolicy
ENCLR_NAME DEFAULT CURRENT
============================================
ENC0 Round-Robin Round-Robin
The DMP statistics are now reset:
# vxdmpadm iostat reset
With the workload still running, the effect of changing the I/O policy to balance
the load across the primary paths can now be seen.
# vxdmpadm iostat show dmpnodename=c3t2d15 interval=5 count=2
.
.
.
cpu usage = 14403us per cpu memory = 32768b
OPERATIONS KBYTES AVG TIME(ms)
PATHNAME READS WRITES READS WRITES READS WRITES
c2t0d15 1021 0 1021 0 0.39 0.00
c2t1d15 947 0 947 0 0.39 0.00
c3t1d15 1004 0 1004 0 0.39 0.00
c3t2d15 1027 0 1027 0 0.40 0.00
c4t2d15 1086 0 1086 0 0.39 0.00
c4t3d15 1048 0 1048 0 0.39 0.00
c5t3d14 1036 0 1036 0 0.39 0.00
c5t4d15 1021 0 1021 0 0.39 0.00
The enclosure can be returned to the single active I/O policy by entering the
following command:
# vxdmpadm setattr enclosure ENC0 iopolicy=singleactive
Next the dd command is used to apply an input workload from the volume:
181Administering Dynamic Multipathing
Administering DMP using vxdmpadm