Disk drive modules

The disk drive modules contain the data for your storage unit.

Disk drive modules (DDMs) are magnetic nonvolatile media that are used to store and manage application and system data. The DDMs are installed in the front of the server or expansion enclosure in a horizontal orientation with the locking handle to the left. DDMs are located in rows and columns on the front of the expansion or server enclosure.

Each server or expansion enclosure must contain a minimum of 4 DDMs. You can install a maximum of 16 DDMs per server or expansion enclosure. You must add DDMs to the storage unit in groups of 4 DDMs of the same type. DDMs must be populated in rows. The first row of 4 DDMs must be placed at the top of the enclosure followed by the second row, then the third and finally, the fourth row. The positions of the DDMs in the storage unit are shown in Figure 1.

Figure 1. Close view of the disk drive modules

Front view of DS6000 server storage unit

If you choose to configure your storage unit with fewer than 16 DDMs, you must populate the empty DDM slots with disk drive module blanks to prevent your storage unit from overheating. A drawing of the DDM blank is shown in Figure 2.

Figure 2. DDM blank

There are different types of fibre-channel arbitrated loop (FC-AL) DDMs.

Note: Server enclosures only support one DDM type. Once the server enclosure is populated with a DDM type, all remaining DDMs must be of the same type.

Each DDM contains a Ready indicator and a Check/identify indicator. The color and state descriptions of these indicators are explained in Table 1.

Table 1. DDM Indicators
Indicator name (color)	Purpose	State descriptions
Ready (green)	Indicates the status of the DDM resource.	Solid: Indicates that both ports are active and that the DDM is idle. Flashing (fast): Indicates that the DDM is processing one or more commands and that both device adapter ports are active. Flashing (slow): Indicates that only one device adapter port is active. Off: The DDM is not receiving power.
Check/identify (amber)	Indicates the fault or identification status of the DDM resource.	Solid: Indicates one of three states: Power on diagnostics are running A fault has been detected The device is in service mode and is ready for removal Flashing (slow): Identifies the DDM as a failing resource. Off: Indicates that there is no fault or no power condition.