DDD (Defunct Disk Drive) or DHS (Defunct Hot Spare)

1. Gently unlatch the hard disk drive tray latch fully, but do not slide it any further from the drive bay.
2. Wait at least 20 seconds to allow the hard disk drive to spin down.
3. Carefully slide the hard disk drive from the bay without inducing shocks or jolts on the hard disk drive.
4. Wait at least 30 seconds from the time the hard disk drive was unlatched before installing a hard disk drive back into the bay.
   
   Note: If the logical drive is not offline, a rebuild automatically occurs when a good hard disk drive is installed in the bay.

from IBM Support Site