An allocation policy with the balance allocation order can be defined and assigned to files that must have their allocations distributed at random between a set of specified volumes. Each extent associated with these files are limited to a maximum size that is defined as the required chunk size in the allocation policy. The distribution of the extents is mostly equal if none of the volumes are full or disabled.
Load balancing allocation policies can be assigned to individual files or for all files in the file system. Although intended for balancing data extents across volumes, a load balancing policy can be assigned as a metadata policy if desired, without any restrictions.
If a file has both a fixed extent size set and an allocation policy for load balancing, certain behavior can be expected. If the chunk size in the allocation policy is greater than the fixed extent size, all extents for the file are limited by the chunk size. For example, if the chunk size is 16 MB and the fixed extent size is 3 MB, then the largest extent that satisfies both the conditions is 15 MB. If the fixed extent size is larger than the chunk size, all extents are limited to the fixed extent size. For example, if the chunk size is 2 MB and the fixed extent size is 3 MB, then all extents for the file are limited to 3 MB.