Enabling GNA on a cluster requires, starting with OneFS v7.x and greater, there is a requirement where more than 1.5% of SSD space as well as greater than 20% of the nodes with SSD.  Typically, the standard X and S nodes (with SSD included) have enough SSD capacity to manage the MetaData within the pool of nodes that contain the SSD drives.  The challenge is when the cluster has more capacity than the 2% the SSD can accommodate. In this regard, only the SSD loaded node pools will accelerate by default. This function is not impacted by enabling the GNA enable/disable function within the SmartPools setting.  Enabling GNA in SmartPools will accelerate MetaData for all pools (if the SSD requirements are met). Disabling GNA just sets pool based MetaData acceleration.  Of course, the cluster acceleration policy can be changed at any time by changing the directories or files the administrator wishes to change.
What happens to a cluster with SSD but the Global Namespace Acceleration (GNA) is disabled or if the cluster does not have enough SSD to accelerate the MetaData?
What happens to a cluster with SSD but the Global Namespace Acceleration (GNA) 
is disabled or if the cluster does not have enough SSD to accelerate the 
MetaData?