Explanation Since both drives are in different RAID 1 arrays and both are hot-swappable, the most efficient step is to replace both failed drives at the same time. This can minimize the downtime and avoid unnecessary reboots. RAID 1 provides mirroring, which means that data is duplicated on both drives in the array. Therefore, replacing one drive will not affect the data on the other drive or the functionality of the array. References: https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_1