Dell EMC PowerVault MD 34XX/38XX Series Storage Arrays Administrator's Guide

If the amount of space used by the host for read/write operations (sometimes called consumed capacity) exceeds the amount of physical capacity allocated on a standard virtual disk, the storage array cannot accommodate additional write requests until the physical capacity is increased. However, on a thin virtual disk, MD Storage Manager can automatically expand physical capacity of a thin virtual disk. You can also do it manually using Storage > Virtual Disk > Increase Repository Capacity. If you select the automatic expansion option, you can also set a maximum expansion capacity. The maximum expansion capacity enables you to limit the automatic growth of a virtual disk to an amount less than the defined virtual capacity.