Dell POWERVAULT MD3600F - Manual (Page 49)

Planning: MD3600f Series Storage Array Terms and Concepts 49
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
• Foreground initialization
• Consistency check
• Rebuild
• Copy back
If a redundant RAID controller module fails with existing virtual disk
processes, the processes on the failed controller are transferred to the peer
controller. A transferred process is placed in a suspended state if there are four
active processes on the peer controller. The suspended processes are resumed
on the peer controller when the number of active processes falls below four.
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