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L3 cache is enabled per node pool through a simple on or off configuration setting. Otherwise, there are no additional visible configuration settings to change. When enabled, L3 cache consumes all the SSD in node pool. Also, L3 cache cannot co-exist with other SSD strategies except for Global Namespace Acceleration (GNA). However, because they are exclusively reserved, L3 cache node pool SSDs cannot participate in GNA.
Note: L3 cache is enabled by default on any new node pool containing SSDs.
There is also a global setting to enable L3 cache by default for new node pools.
When converting the SSDs in a particular node pool to use L3 cache rather than SmartPools, you can estimate progress by periodically tracking SSD space usage (used capacity) during the conversion process. Also, you can change the job impact policy of the Flexprotect_Plus or SmartPools job responsible for the L3 cache conversion so that the job runs faster or slower. This change increases or decreases the impact of the conversion process on cluster resources.
Note: Node pools with L3 cache enabled are invisible for GNA purposes. All GNA ratio calculations are done exclusively for node pools without L3 cache enabled. For example, if you have six node pools on your cluster, and three of them have L3 cache enabled, GNA is applied only to the three remaining node pools without L3 cache enabled. On node pools with L3 cache enabled, metadata does not need an additional GNA mirror because L3 cache already accelerates metadata read access.