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

Every virtual disk must be initialized. Initialization is done in the background automatically, however the priority can be modified by updating the Change Modification Priority option. This change can affect the performance of the array until the initialization is complete. A maximum of four virtual disks can be initialized concurrently on each RAID controller module.

The storage array executes a background initialization when the virtual disk is created to establish consistency, while allowing full host server access to the virtual disks. Background initialization does not run on RAID 0 virtual disks. The background initialization rate is controlled by MD Storage Manager. To change the rate of background initialization, you must stop any existing background initialization. The rate change is implemented when the background initialization restarts automatically.