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

The media verification operation runs only on selected disk groups, independent of other disk groups. Cycle time is the time taken to complete verification of the metadata region of the disk group and all virtual disks in the disk group for which media verification is configured. The next cycle for a disk group starts automatically when the current cycle completes. You can set the cycle time for a media verification operation between 1 and 30 days. The storage controller throttles the media verification I/O accesses to disks based on the cycle time.

The storage array tracks the cycle for each disk group independent of other disk groups on the RAID controller and creates a checkpoint. If the media verification operation on a disk group is preempted or blocked by another operation on the disk group, the storage array resumes after the current cycle. If the media verification process on a disk group is stopped due to a RAID controller module restart, the storage array resumes the process from the last checkpoint.