| Measurement |
Description |
Measurement Unit |
Interpretation |
| Zeroing_disks |
Indicates the number of disks that are currently zeroing in this storage system. |
Number |
Disk zeroing is usually a time consuming background operation that is used to initialize the spare disks before they can be used. Disk zeroing is the process of formatting the disk by filling zeroes i.e., overwriting the files with zeroes before being used. |
| Offline_disks |
Indicates the number of disks that are currently offline in this storage system. |
Number |
Unresponsive or semi-responsive disks are taken offline by the operating system and its data is reconstructed from the associated parity disks. This puts a strain on the performance of the associated RAID group. Irrecoverable offline disks will be failed. |
| Broken_disks |
Indicates the number of disks whose RAID status is Broken in this storage system. |
Number |
The disks may be broken due to disk failure, labeling issues or intentional setting to phsyical removal. Broken disks affect constituent raid group performance and put the system at risk of losing data if spares are unavailable. |
| Media_scrub_completed |
Indicates the average percentage of media scrubbing that is currently completed across all spare disks in this storage system. |
Percent |
Media scrubbing is a continuous background process. The purpose of the continuous media scrub is to detect and correct media errors in order to minimize the chance of storage system disruption due to a media error while a storage system is in degraded or reconstruction mode.
By default, Data ONTAP runs continuous background media scrubbing for media errors on all storage system disks. If a media error is found, Data ONTAP uses RAID to reconstruct the data and repairs the error.
Due to media scrubbing process, the disk LEDs may blink on an apparently idle storage system and some CPU activity may occur even when no user workload is present. |