Dell PowerVault ME5 Series Administrator's Guide

Disk-group scrub

The disk-group scrub utility analyzes specified disk groups to find and fix errors. It can find media errors for any protection level and for a read cache disk group. By default, the utility is enabled to run periodically.

The disk-group scrub utility acts on all disks in the disk group, but not leftover disks. The disk-group scrub utility performs these tasks:

• Checks redundancy data (parity) and corrects it for protection levels 5, 6, and ADAPT .
• Finds, but does not fix, mirror mismatches for protection levels 1 and 10.
  • The system reads both copies of mirror data to find any mismatches.
• Finds and fixes media errors for all redundant protection levels.
  • Media errors occur when the system cannot read one of the copies of mirror data, due to a disk error such as an Unrecoverable Read Error (URE).
  • (RAID-1 and RAID-10). Verify that all blocks are readable (NRAID and RAID-0).

A disk-group scrub can last well over an hour, depending on disk-group size, utility priority, and the amount of I/O activity. You can use a disk group while it is being scrubbed. While the scrub is running, you can monitor progress and cancel if necessary. When the scrub is complete, event 207 is logged.

To run the scrub utility, see Scrubbing a disk group.