Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

cpu usage = 11294us per cpu memory = 32768b
OPERATIONS KBYTES AVG TIME(ms)
PATHNAME READS WRITES READS WRITES READS WRITES
c2t0d15 0 0 0 0 0.00 0.00
c2t1d15 0 0 0 0 0.00 0.00
c3t1d15 0 0 0 0 0.00 0.00
c3t2d15 0 0 0 0 0.00 0.00
c4t2d15 0 0 0 0 0.00 0.00
c4t3d15 0 0 0 0 0.00 0.00
c5t3d15 0 0 0 0 0.00 0.00
c5t4d15 5493 0 5493 0 0.41 0.00
The vxdmpadm command is used to display the I/O policy for the enclosure that
contains the device:
# vxdmpadm getattr enclosure ENC0 iopolicy
ENCLR_NAME DEFAULT CURRENT
============================================
ENC0 MinimumQ Single-Active
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 MinimumQ 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
Administering Dynamic Multi-Pathing
Administering DMP using vxdmpadm
186