HP StorageWorks XP Remote Web Console Software - Manual (Page 16)

16 Performance Control XP
5. Set an upper limit to traffic between ports and the non-prioritized WWN. To maintain sufficient I/O
rates at prioritized WWNs, set upper limit values for the I/O rate for non-prioritized WWNs. When
you first set an upper limit, HP recommends that the upper limit be approximately 90 percent of peak
traffic.
In network B, the peak I/O rate is 200 IO/s on the paths between the non-prioritized WWNs (wwn02
and wwn03) and all four ports on the disk array (1A, 1C, 2A, and 2C). Therefore, the recommended
upper limit for non-prioritized WWNs is 720 IO/s (200 x 4 x 0.90).
If your network is configured like network B, perform the following steps (see
Figure 8 ):
a. In the WWN tab, click one of the four ports to which the HBAs are connected (1A, 1C, 2A, or 2C).
b. Set an upper limit for the non-prioritized WWNs (wwn02 and wwn03).
Figure 8 Setting upper limits
Figure 9 shows the result of setting an upper limit of 720 IO/s to the paths between 1A and the
non-prioritized WWNs. For details, see ” Setting upper limit values for HBAs in a PFC group ” on
page 26.
6. Check the result of applying upper limit values. Measure traffic at ports and view traffic statistics for the
prioritized WWN to check whether host performance improved to a desirable level.
In network B, the desirable I/O rate for the prioritized WWN is 400 IO/s. If production server
performance has not achieved the desired level, lower the value of the upper limit and apply the new
upper limit to the disk array. In network B, if the upper limit is set to 720 IO/s but the I/O rate for
wwn01 remains below 400 IO/s, lower the upper limit until the I/O rate reaches 400 IO/s.
7. If necessary, apply a threshold. Set a threshold in the WWN tab of the Performance Control pane.
In the WWN tab, specify only one threshold for the entire subsystem, 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 non-prioritized WWNs is disabled when the sum of the I/O rates for all
prioritized WWNs goes below 100 IO/s.
For details, see ”
Setting thresholds ” on page 24.
Notes on using Performance Control XP
• User types. Users belonging to the StorageAdmins group cannot use Performance Control XP. For more
information about limitations, see the HP StorageWorks Command View XP User Guide for XP Disk
Arrays or the HP StorageWorks XP Remote Web Console User Guide for the specific disk array.
• I/O rates and transfer rates. Performance Control XP is based on I/O and transfer rates measured by
Auto LUN/Performance Control Base Monitor. Auto LUN/Performance Control Base Monitor measures
I/O and transfer rates every second, and calculates the average I/O and average transfer rates for
every gathering interval (specified between 1 and 15 minutes) regularly.
Suppose that 1 minute is specified as the gathering interval and the I/O rate at port 1-A changes as
illustrated in Figure 9 Graph 1. When you display the I/O rate graph for 1A in Auto LUN/Performance
Control Base Monitor, the line in the graph indicates changes in the average I/O rate calculated every
minute (see Graph 2). If you click the Detail check box in the Auto LUN pane, the graph displays
changes in maximum, average, and minimum I/O rates in one minute.
Performance Control XP applies upper limits and thresholds to the average I/O or transfer rate
calculated every gathering interval. For example, in Figure 9 (which has a gathering interval of 1
minute), if you set an upper limit of 150 IO/s to port 1A, the highest data point in the line CL1-A in