Lenovo THINKSERVER 3821 - Manual (Page 174)

The following illustration shows the internal SAS/SATA cable routing and connectors
from the ServeRAID MR10i or ServeRAID MR10is controllers to eight 2.5-inch hard
disk drives. The right port on the ServeRAID MR10i or ServeRAID MR10is
controller is connected to the backplane for drives 4-7 and the left port on the
controller is connected to the backplane for drives 0-3.
1 Cable for drives 4 - 7
2 Cable connector for drives 4 - 7
3 Cable for drives 0 - 3
4 Cable connector for drives 0 - 3
The following illustration shows the cable connectors on the ServeRAID-MR10i
controller.
1 ServeRAID-MR10i controller
2 Cable connector for drives 4 - 7
3 Cable connector for drives 0 -3
4 Battery
166 ThinkServer TD200x Types 3719, 3821, 3822, and 3823: Hardware Maintenance Manual