HP XP Array Manager Software - Manual (Page 27)

I/O rate for prioritized ports (1A and 1C) at 400 IO/s. To maintain the I/O rate at 400 IO/s,
you must set an upper-limit to the I/O rate for the port 2A.
Figure 7 Traffic at ports
.
For detailed information about monitoring traffic, see “ Setting Priority for Ports on the Storage
System ” on page 34 and “ Analyzing Traffic Statistics in the Port Tab ” on page 33.
3. Set an upper-limit for the I/O rate for traffic at the non-prioritized port. To prevent decline in I/O
rates at prioritized ports, you set upper-limit values to the I/O rate for non-prioritized ports.
When you set an upper-limit for the first time, HP recommends that the upper-limit be approximately
90 percent of the peak traffic. In network A, the peak I/O rate for the non-prioritized port (2A)
is 200 IO/s. So, the recommended upper-limit for 2A is 180 IO/s.
For details on how to set an upper-limit, see “
Setting Upper-Limit Values to Traffic at Non-prioritized
Ports ” on page 34.
4. Check the result of applying upper-limit values. After applying upper-limit values, you must
measure traffic at ports. You must view traffic statistics for prioritized ports 1A and 1C to check
whether the host performance is improved to a desirable level.
In network A, the desirable I/O rate for ports 1A and 1C is 400 IO/s. If the I/O rate reaches
400 IO/s, production server performance is at a desirable level. If production server performance
is not improved enough, you can change the upper-limit to a smaller value and then apply the
new upper-limit to the storage system. In network A, if the upper-limit is set to 180 IO/s but the
I/O rates for 1A and 1C are still below 400 IO/s, the administrator needs to change the upper
limits until the I/O rates reach 400 IO/s.
5. If necessary, apply a threshold. To use the threshold control, set threshold values in the Port tab
in the Performance Control window. You can set threshold values in either of the following ways:
• Set one threshold for each prioritized port.
In network A, if you set a threshold of 200 IO/s for port 1A and set a threshold of 100 IO/s
for port 1C, the upper limit on the non-prioritized port (2A) is disabled when either of the
following conditions is satisfied:
• The I/O rate for port 1A is 200 IO/s or lower
• The I/O rate for port 1C is 100 IO/s or lower
• Set only one threshold for the entire storage system
In network A, if you set a threshold of 500 IO/s for the storage system, the upper limit on the
non-prioritized port (2A) is disabled when the sum of the I/O rates for all prioritized ports
(1A and 1C) goes below 500 IO/s.
For details on how to set a threshold, see “ Setting a Threshold in the Port Tab ” on page 35.
XP24000/XP20000 Performance Control User Guide 27