Dell PowerEdge M620 Owner's Manual page 32

The hard-disk drives plug into the internal storage backplane inside the blade.
On blades with a diskless configuration, all hard drive slots must be filled with
hard drive blanks, and the internal storage backplane must still be installed to
maintain proper airflow.
See Figure 1-14 for information on the hard-drive indicators. Different
patterns are displayed as drive events occur in the system.
NOTE:
The blade must have a hard drive or a hard-drive blank installed in each
hard-drive bay.
NOTE:
The hard-drive status indicator is only functional for RAID hard drive
configurations. For non-RAID configurations, only the drive-activity indicator is
active. Refer to the RAID controller documentation to service a RAID volume,
rebuild an array, or swap RAID members.
Figure 1-14. Hard-Drive Indicators
1 drive-activity indicator (green)
32
About Your System
2
1
2 drive-status indicator (green and
amber)