When to Add the First Read Cache Device (BUI)
Use the following procedure to determine if you need a first read cache device for the
appliance. To determine if you need more than one device, see When to Add More Read Cache Devices (BUI).
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Create a worksheet as described in Creating a Worksheet (BUI).
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Click the add icon
next to Add statistic.
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Go to CACHE > ARC accesses > Broken down by hit/miss.
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Click metadata hits under the Range average column to show the graph of ARC accesses
per second, broken down by hit/miss.
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Click the drilldown icon
and select By L2ARC eligibility.
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Click data hits to show the graph of ARC accesses per second, broken down by
hit/miss.
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Click the drilldown icon
and select By L2ARC eligibility.
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Wait several minutes.
Note -
This wait time can be adjusted to better determine your peak I/O. Capturing
analytics for 24 hours during normal business operations may reveal the best
understanding of your IO patterns.
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Examine the graphs.
Consider adding the first read cache device when all of the following conditions are
present: