An ALUA I/O is issued asynchronously with an I/O operation performed by the user on the non-preferred path side, and therefore an I/O from the server might continue on a volume on the storage system connected to the non-preferred path if a remote path failure occurs. This might cause an unintended switchover between the preferred and non-preferred paths.
When you set I/O preference mode when remote path failed, a path connected to a P-VOL can be set for the preferred path if a remote path failure occurs, which prevents an unintended switchover between the preferred and non-preferred paths