HP StorageWorks XP24000/XP20000 Performance Control User's Guide (T5214-96047, December 2008)

• Measure traffic between port 2A and the three HBAs.
• Measure traffic between port 2C and the three HBAs.
Figure 11 on page 32 illustrates the I/O rate using the paths between each port and the HBAs.
According to the graph, the I/O rate using the path between 1A and the prioritized WWN
(wwn01) was approximately 400 IO/s at first. The I/O rate using the path between 1A and the
non-prioritized WWNs (wwn02 and wwn03) was approximately 100 IO/s at first. However,
as the I/O rate for non-prioritized WWNs (wwn02 and wwn03) gradually increased from 100
IO/s to 200 IO/s, the I/O rate for the prioritized WWN (wwn01) decreased from 400 IO/s to
200 IO/s. This indicates that the high-priority production server has degraded.
For more information about monitoring traffic, see “Setting Priority for Host Bus Adapters” on page
42 and “Analyzing Traffic Statistics” on page 41.
Figure 11 Traffic at ports
5. Set an upper-limit to traffic between ports and the non-prioritized WWN to prevent decline in
I/O rates at prioritized WWNs.
When you set an upper-limit for the first time, the upper-limit should be approximately 90 percent
of the peak traffic level.
In network B, the peak I/O rate using the paths between port 1A and the non-prioritized WWNs
(wwn02 and wwn03) is 200 IO/s. The peak I/O rate using the paths between port 1C and the
non-prioritized WWNs is also 200 IO/s. The peak I/O rate using the paths between port 2A
and the non-prioritized WWNs is also 200 IO/s. The peak I/O rate using the paths between
port 2C and the non-prioritized WWNs is also 200 IO/s. So, the recommended upper-limit for
the non-prioritized WWNs is 720 IO/s (= 200 × 4 × 0.90).
If your network is configured as in Figure 8 on page 30, you must do the following in this order
(see Figure 12 on page 33):
a. In the WWN tab, select one of the four ports that the HBAs are connected to (that is, ports
1A, 1C, 2A, or 2C).
b. Set an upper-limit to the non-prioritized WWNs (wwn02 and wwn03).
Figure 12 on page 33 is the result of setting the upper-limit of 720 IO/s using the paths between
1A and the non-prioritized WWNs. For details on how to set an upper-limit, see
“Setting Upper-Limit Values to Traffic at Non-prioritized Ports” on page 36.
XP Performance Control Operations32