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Optimize access cache performance

Contributors netapp-aherbin
PDFs

You can configure several parameters to optimize the access cache and find the right balance between performance and how current the information stored in the access cache is.

About this task

When you configure the access cache refresh periods, keep the following in mind:

  • Higher values mean entries stay longer in the access cache.

    The advantage is better performance because ONTAP spends less resources on refreshing access cache entries. The disadvantage is that if export policy rules change and access cache entries become stale as a result, it takes longer to update them. As a result, clients that should get access might get denied, and clients that should get denied might get access.

  • Lower values mean ONTAP refreshes access cache entries more often.

    The advantage is that entries are more current and clients are more likely to be correctly granted or denied access. The disadvantage is a decrease in performance because ONTAP spends more resources refreshing access cache entries.

Steps

  1. Set the privilege level to advanced:

    set -privilege advanced

  2. Perform the desired action:

    To modify the…​ Enter…​

    Refresh period for positive entries

    vserver export-policy access-cache config modify-all-vservers -refresh-period-positive timeout_value

    Refresh period for negative entries

    vserver export-policy access-cache config modify-all-vservers -refresh-period-negative timeout_value

    Timeout period for old entries

    vserver export-policy access-cache config modify-all-vservers -harvest-timeout timeout_value

  3. Verify the new parameter settings:

    vserver export-policy access-cache config show-all-vservers

  4. Return to the admin privilege level:

    set -privilege admin