HP StorageWorks P9000 Performance Advisor Software v5.4 Troubleshooting and FAQs Guide (T1789-96336, April 2012)

• Sequential MB Writes
The above mentioned metrics are not supported in P9000 Performance Advisor for the continuous
access journal pool LDEVs.
In charts, the following metrics are disabled for the LDEVs that belong to the continuous access journal
pools:
• FrontEnd IO metrics: LDEV Random Writes and LDEV Sequential Writes
• FrontEnd MB metrics: Random MB Write and Sequential MB Write
• Response Time metrics: Maximum Write Response and Average Write Response
Predict variations in LDEVs response time
NOTE:
Viewing variations in LDEVs response time is a new feature introduced in P9000 Performance Advisor
from v4.6 onwards. Therefore, these FAQs are not applicable to P9000 Performance Advisor versions
prior to v4.5.
Can I set the duration for P9000 Performance Advisor to predict the average
read and write response time of LDEVs?
Yes. You can set the duration that P9000 Performance Advisor must use to predict the average read
and write response time of LDEVs.
Complete the following steps to select the duration:
1. Click Settings in the left pane.
2. Select User Settings.
The User Settings screen appears.
3. In the Data Analysis Settings section, select the duration from the drop-down list. You can select
a maximum of 7 days. By default, P9000 Performance Advisor considers a duration of 2 days
for the prediction.
4. Click Save.
What is the minimum and maximum duration that can be set?
You can select a maximum of 7 days. By default, P9000 Performance Advisor considers a minimum
duration of 2 days for the prediction.
Can you provide a use case on why it is necessary to predict variations in LDEVs
response time?
Consider that your application has association with multiple LDEVs and is experiencing slow response
time. Because some of the resources, such as RAID group and CHIP MP are shared, their utilization
might not indicate an impact on the application in question. Instead, you can identify the LDEV that
is experiencing variations in its response time by analyzing the LDEV's read and write response time
values. Then, you can verify the utilization of associated resources, such as CHIP MP, RAID group,
and DKA to take the appropriate action. You can view performance graphs related to other metrics
and analyze the cause for the performance load on the LDEVs.
HP StorageWorks P9000 Performance Advisor Software Frequently Asked Questions 83