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Changing the cache size emulated by PCS

If Predictive Cache Statistics (PCS) is enabled on your storage system, you can change the size of cache emulated by PCS to better predict how a caching module would handle your workloads. The size of cache allowed depends on the amount of memory in the controller.

Before you begin

PCS must be enabled.

About this task

The flexscale.pcs_size option changes the cache size emulated by PCS. This option is used only when PCS is enabled (setting flexscale.enable to on), and your storage system does not have a caching module installed.

This command is available through the nodeshell. You access the nodeshell by using the system node run command. For more information, see the man page.

Steps

  1. Enter the following command to view the current cache size emulated by PCS: options flexscale.pcs_size
    The default value is chosen automatically based on the amount of memory in the controller.
  2. Enter the following command to change the size of cache emulated by PCS: options flexscale.pcs_size integer

    You can specify integers between 16 and 16383.