There are four different configuration options, Tuning, Read Ahead, Sync Always, and Dirty Threshold Percent. There are several options for each of these parameters that affect the behavior of the Cache:
•Tune Cache For – This parameter controls the cache line size and how the Cache works with the back end Flash Array. The two options are:
oIOPS – Use a smaller cache line size and send smaller accesses to the RAID controller. This setting is recommended for storage workloads that tend to us 64KB or smaller accesses (most database workloads).
oBandwidth – Use a larger cache line size and send large accesses to the RAID that access multiple Flash modules in parallel. This setting is recommended for data acquisition or for a small number of users that need high bandwidth (some data warehouse workloads).
•Read Ahead – The read ahead setting controls whether the cache attempts to read additional data ahead of the location of a read. This can help improve performance in a highly sequential read environment, but wastes cache space under a random workload. The higher the setting the more read ahead is attempted.
•Sync Always – This parameter controls whether the cache will always attempt to sync to the back end Flash. When the box is checked, this feature is enabled.
•Dirty Threshold Percent – This parameter controls how much of the cache can be used for storing dirty data (data that has been written to Flash but has not yet been written to disk) before the system gives syncing the dirty data to Flash a higher priority.
4.13Viewing the Logs with the Web Monitor
Perhaps the most important part of the Web monitor is the system event log. This log keeps track of all events that occurred within the system. If you are having trouble with your system, be sure to open the system event log and check this information.
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