The goal of the AutoBalance job is to ensure that each node has the same amount of data on it so that data is evenly balanced across the cluster. AutoBalance, along with the Collect job, runs after any cluster group change, unless there are any storage nodes in a down state.
Upon visiting each file, AutoBalance performs the following two operations:
For file-level rebalancing, AutoBalance evenly spreads data across the cluster’s nodes to achieve balance within a particular file. With full-array rebalancing, AutoBalance moves data between nodes to achieve an overall cluster balance within a 5 percent delta across nodes.
Also available is an AutoBalanceLin job, which automatically runs in place of AutoBalance when the cluster has a metadata copy available on SSD. AutoBalanceLin provides an expedited job runtime.