What must be done if you add a new disk and the previous disks are configured in a RAID?

When you add a new disk to a RAID configuration, particularly if the RAID setup requires it, the RAID array must be rebuilt to integrate the new disk correctly. Rebuilding the RAID array involves using the new disk to expand the existing RAID volume or to replace a failed disk, depending on the specific RAID level you are using. This process allows the RAID controller to redistribute data across all available disks, ensuring data redundancy, performance, and integrity.

Simply adding a disk without any further action does not automatically adjust the RAID configuration or utilize the new disk effectively. Recreating the entire RAID configuration would entail losing existing data and is not practical when simply adding a new disk. Formatting the new disk only pertains to treating it as an independent volume, which would not be suitable for maintaining the characteristics and benefits of the RAID setup.

Therefore, to maintain the RAID level's intended functionality and ensure its performance, the correct step is to rebuild the RAID array, which incorporates the new disk into the established data structure.