HP XP P9000 for Compatible High Perf FICON Connectivity Software - Manual (Page 53)

If an upper limit of the non-prioritized WWN is set to zero or nearly zero, I/O performance
might be lowered. If I/O performance is lowered, the host cannot be connected to the storage
system in some cases.
7. If necessary, apply a threshold. If you want to use threshold control, set a threshold in the
WWN tab in the Performance Control main window.
In the WWN tab, you can specify only one threshold for the entire storage system, regardless
of the number of prioritized WWNs. For example, if there are three prioritized WWNs in the
network and the threshold is 100 IO/s, the upper limit on the non-prioritized WWNs is
disabled when the sum of the I/O rates for all prioritized WWNs goes below 100 IO/s.
For details on how to set a threshold, see “Setting a threshold” (page 62) .
CAUTION: If you enter zero (0) in a cell to disable the upper limit, the cell displays a hyphen
(-) and the threshold for the prioritized port becomes ineffective. If the thresholds of all the
prioritized ports are ineffective, threshold control will not be performed but upper limit control
will be performed.
The following table shows the relationship between thresholds of a prioritized WWN and the
upper limits of a non-prioritized WWN.
Table 5 Prioritized WWN threshold setting relationships
Zero is set to the upper limit of the
non-prioritized WWN A number other than zero is set to the upper
limit of the non-prioritized WWN Threshold settings
The threshold control of the prioritized WWN
is not executed. When thresholds are set to prioritized
WWNs, depending on the I/O rate or the Threshold Is Set to The
Prioritized WWN
transfer rate, the following controls are
executed.
• If the total value of I/O rate or transfer rate
exceeds the threshold in all prioritized
WWNs, upper limits of all the
non-prioritized WWNs take effect.
•
If the total value of I/O rate or transfer rate
goes below the threshold in all prioritized
WWNs, upper limits of all the
non-prioritized WWNs do not take effect.
The specified upper limit always takes effect. Threshold Is Not Set to
The Prioritized WWN
Port tab operations
If one-to-one connections are established between host bus adapters (HBAs) and storage system
ports, use the Port tab in the Performance Control main window to do the following:
•
Analyze traffic statistics
•
Measure traffic between host bus adapters and storage system ports
•
Set priority to ports on the storage system
•
Set an upper limit to traffic at each non-prioritized port
•
Set a threshold to the storage system or to each prioritized port, if necessary
If one-to-one connections are established between host bus adapters and ports, you should specify
the priority of I/O operations on each port. You can specify the upper limit values on the
non-prioritized ports, and if necessary, you can also specify the threshold values on the prioritized
ports. Moreover, you can use one threshold value applied for the entire storage system.
Port tab operations 53