Volume Balancer

Describes the role of the volume balancer.

Volume balancer is used to distribute containers of a volume on all the storage pools that belong to the volume’s topology. Although the disk balancer balances containers across storage pools, sometimes containers of a volume may accumulate on a few storage pools. For example:

• When the storage pools hosting a volume’s containers are not highly utilized, the disk balancer might not spread the volume’s containers across storage pools.
• When new storage pools are added to a topology and the storage pools on which the current containers reside are not highly utilized, although the disk balancer moves containers to new storage pools, it is not guaranteed that a specific volume’s containers are evenly spread out.

In such cases, you can trigger the balancing of a volume using a maprcli command. Every time a volume gets out of balance, you can trigger the volume balancer (using the maprcli command) to balance the containers associated with the volume. The container moves triggered by disk and volume balancers do not cause other volumes to be imbalanced.