Traffic at ports – HP XP Array Manager Software User Manual
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Figure 7 Traffic at ports
For detailed information about monitoring traffic, see
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Setting Priority for Ports on the Storage System
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, it is recommended that the upper-limit be approx-
imately 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
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Setting Upper-Limit Values to Traffic at Non-prioritized Ports
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:
• Specify one threshold for each prioritized port.
In network A, if you specify a threshold of 200 IO/s for the port 1A and specify a threshold
of 100 IO/s to the 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 the port 1A is 200 IO/s or lower.
• The I/O rate for the port 1C is 100 IO/s or lower.
• Set only one threshold to the entire storage system
In network A, the desirable 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) reach 500 IO/s.
For details on how to set a threshold, see “
XP24000/XP20000 Performance Control User's Guide
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