The 3DFS cache size must be at least 30% of the size of the data that you want to restore from the backup set or the subclient.
By default, the 3DFS cache is located in the jobResults/3dfs directory. To specify a different path, see Configuring the 3DFS Cache from the CommCell Console.
For better performance, Commvault recommends using a solid-state drive (SSD) for the 3DFS cache.