Dell PowerVault MD3200i Owner's Manual - Page 44
Media Verification, Cycle Time, Virtual Disk Operations Limit
View all Dell PowerVault MD3200i manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 44 highlights
A consistency check is similar to a background initialization. The difference is that background initialization cannot be started or stopped manually, while consistency check can. NOTE: Dell recommends that you run data consistency checks on a redundant array at least once a month. This allows detection and automatic replacement of unreadable sectors. Finding an unreadable sector during a rebuild of a failed physical disk is a serious problem, because the system does not have the redundancy to recover the data. Media Verification Another background task performed by the storage array is media verification of all configured physical disks in a disk group. The storage array uses the Read operation to perform verification on the space configured in virtual disks and the space reserved for the metadata. Cycle Time 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 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. Virtual Disk Operations Limit The maximum number of active, concurrent virtual disk processes per RAID controller module installed in the storage array is four. This limit is applied to the following virtual disk processes: • Background initialization 44 Planning: MD3200i Series Storage Array Terms and Concepts