Asus PIKE 2108 - Manual (Page 54)

2-40 Chapter 2: RAID configuration
2. Scenario #2: If some of the drives in a configuration are removed
and re-inserted, the controller considers the drives to have foreign
configurations.
Import or clear the foreign configuration. If you select Import, automatic
rebuilds will occur in redundant virtual drives.
Start a consistency check immediately after the rebuild is complete to ensure
data integrity for the virtual drives.
3. Scenario #3: If all the drives in a virtual drive are removed, but at
different times, and re-inserted, the controller considers the drives to
have foreign configurations.
Import or clear the foreign configuration. If you select Import, all drives
that were pulled before the virtual drive became offline will be imported
and then automatically rebuilt. Automatic rebuilds will occur in redundant
virtual drives.
4. Scenario #4: If the drives in a non-redundant virtual drive are removed,
the controller considers the drives to have foreign configurations.
Import or clear the foreign configuration. No rebuilds will occur after
the import operation because there is no redundant data to rebuild the
drives with.