Disk media error failure thresholds

About media error thresholds

To prevent filer panics or double disk failure due to excessive media errors encountered during single-disk failure reconstruction, Data ONTAP tracks media errors on each active filer disk and sends a disk failure request to the RAID system if system-defined media error thresholds are crossed on that disk.

Disk media error thresholds that trigger a disk failure request include

More than 25 media errors (that are not related to disk scrub activity) occurring on a disk within a 10-minute period
Three or more media errors occurring on the same sector of a disk

If the filer volume is not already running in degraded mode due to single-disk failure reconstruction when the disk failure request is received, RAID will fail the disk in question, swap in a hot spare disk, and begin RAID reconstruction to replace the failed disk.

Failing disks at the thresholds listed in this section ensures that a disk will be replaced before the number of media errors on that disk increases the likelihood of a filer panic or double-disk failure during a single-disk failure reconstruction.