...SOLUTION: This usually occurs when a single-ended drive type is inserted into an enclosure with other drive types; and that makes the entire enclosure operate in single ended mode. To maximize performance replace the single-ended drive with a type that matches the other drives.
Description: One or more single-ended mode SCSI drives are installed in an external storage unit that operates in LVD mode.
Action: The array continues to operate, but installing all LVD drives maximizes performance.