IBM System Storage DS3000, Руководство по программированию

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If you do not want a specific volume to use the Performance Read Cache, you can remove the volume
from the Performance Read Cache by running this command:
set volume ["volumeName"] performanceReadCacheEnabled=FALSE
After you have created the Performance Read Cache, you can model the performance of the Performance
Read Cache to make sure that the Performance Read Cache is running as required for you storage
subsystem
Performance Read Cache performance modeling
After you create the Performance Read Cache, you can run a performance modeling tool to help
determine the best cache size for your storage subsystem.
The performance modeling tool helps you determine the performance improvement for Performance
Read Cache capacity by running a workload on the SSD cache that has the same characteristics as the
workload that you run in production. Performance modeling monitors and measures I/O activity for a
period of time and estimates performance for various Performance Read Cache sizes. The performance
modeling tool then shows the actual performance for the Performance Read Cache that you created.
Depending on the cache capacity and workload, it might take 10 to 20 hours to fully populate the cache.
The cache has valid information even after a run of a few minutes, but the longer that you can run the
performance modeling tool the more accurate the results of the metric data.
The performance modeling tool provides an estimate of performance using these metrics:
v
Cache hit percentage
v
Average response time
Note: Performance modeling does not survive a controller reboot.
Starting and Stopping Performance Read Cache performance modeling
To start a performance modeling operation, use this command:
start performanceReadCache [performanceReadCacheName] performanceModeling
Enclose the identifier in square brackets ([ ]). If the Performance Read Cache name contains special
characters or consists only of numbers, you also must enclose the identifier in double quotation marks ("
") inside square brackets.
After you start the performance modeling operation it will continue to run until you stop the operation.
To stop the performance modeling operation, use this command:
stop performanceReadCache [performanceReadCacheName] performanceModeling
This command immediately stops collecting the performance modeling data and displays the data that
has been collected. The data is displayed in the same window from which you ran the command. If you
prefer, you can save the performance modeling data to a file by running this command:
stop performanceReadCache [performanceReadCacheName] performanceModeling
file="fileName"
fileName
is the file path and the file name to which you want to save the performance modeling data.
Enclose the file name in double quotation marks (" "), as shown in this example:
file="C:\Program Files\CLI\logs\performance.csv"
Chapter 10. Using the Performance Read Cache premium feature
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