The storage on a broken-off mirror should be restored to the original volume during periods of low application I/O load, if possible, because resynchronization and regeneration are I/O-intensive activities that can adversely affect application performance.

Note that if a mirror is regularly broken off from a three-way mirrored volume, susceptibility to failure is greater during the interval between the third-mirror break-off and the completion of resynchronization after the third-mirror storage is returned to the mirrored volume. By performing the restoration during periods of low I/O load, the susceptibility-to-failure window is minimized.