HP XP7 Storage - Manual (Page 47)

Figure 4 Network A: 1-to-1 connections between HBAs and ports
In Network A, ports 1A and 1C are connected to high-priority production servers. Port 2A is
connected to a low-priority development server. Therefore, high priority (Prio.) is set to ports 1A
and 1C, and low priority (Non-Prio.) is set to port 2A. The following figure shows the priority
settings for these ports on the Port tab of the Performance Control main window.
The I/O traffic at the ports is now monitored. When the desired amount of data has been collected,
the traffic statistics are reviewed on graphs using the Performance Monitor window. The following
figure shows the changes in the I/O rate for the three ports (1A, 1C, and 2A). According to the
data, the I/O rate for ports 1A and 1C was approximately 400 IO/s at first, and the I/O rate for
port 2A was approximately 100 IO/s at first. However, as the I/O rate for port 2A gradually
increased from 100 IO/s to 200 IO/s, the I/O rate for ports 1A and 1C decreased from 400
IO/s to 200 IO/s, which indicates that the performance of the high-priority production servers
decreased. If you want to maintain the I/O rate for prioritized ports 1A and 1C at 400 IO/s, you
can set an upper limit to the I/O rate for the non-prioritized port 2A.
When an upper limit is set for the first time, it is recommended 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 port 2A is 180 IO/s. You can then adjust this
value later as needed according to the results of your data analysis.
After upper limit values have been applied, the traffic at the ports is measured to check the result
of the upper limits and see whether host performance has improved to a desirable level, in this
case 400 IO/s for ports 1A and 1C. If production server performance is not improved to a desirable
level, you can adjust the upper limit to a smaller value until the I/O rate for the high priority servers
reaches the desirable level.
Use cases for Performance Control 47