Serial number = 024D0036
Vendor id = 3PARdata
Product id = VV
...
I/O load balance policy = round_robin
...
Driver esdisk Status Information :
Capacity in number of blocks = 2097152
Block size in bytes = 512
Number of active IOs = 0
Special properties =
Maximum number of IO retries = 45
IO transfer timeout in secs = 30
FORMAT command timeout in secs = 86400
START UNIT command timeout in secs = 60
Timeout in secs before starting failing IO = 120
IO infinite retries = false
e.
The default load balancing policy is round robin. HP offers other load balancing options.
HP 3PAR has tested the
round_robin
and
least_cmd_load
load balancing options.
The load balancing policy can be changed globally or for an individual disk.
Example: Issue the following commands to globally change from
round_robin
to
least_cmd_load
:
# scsimgr get_attr -N /escsi/esdisk -a load_bal_policy
SCSI ATTRIBUTES FOR SETTABLE ATTRIBUTE SCOPE : /escsi/esdisk
name = load_bal_policy
current = round_robin
default = round_robin
saved =
# scsimgr set_attr -N /escsi/esdisk -a load_bal_policy=least_cmd_load
Verify it is changed
# scsimgr get_attr -N /escsi/esdisk -a load_bal_policy
SCSI ATTRIBUTES FOR SETTABLE ATTRIBUTE SCOPE : /escsi/esdisk
name = load_bal_policy
current = least_cmd_load
default = round_robin
saved =
Save the load_bal_policy so the change in intact even with reboots.
# scsimgr save_attr -N /escsi/esdisk -a load_bal_policy=least_cmd_load
Verify the change made
# scsimgr get_attr -N /escsi/esdisk -a load_bal_policy
SCSI ATTRIBUTES FOR SETTABLE ATTRIBUTE SCOPE : /escsi/esdisk
name = load_bal_policy
current = least_cmd_load
default = round_robin
saved = least_cmd_load
# scsimgr get_attr -a load_bal_policy -D /dev/rdisk/disk6
26
Allocating Storage for Access by the HP-UX Host
