IBM ServeRAID, User Reference

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ServeRAID-4Mx controller
The ServeRAID-4Mx controller has two independent SCSI channel connectors:
Channel 1 and Channel 2. Each of these SCSI channels supports up to 15 physical
devices.
Note: In the event of a power outage or failure, the battery-backup cache protects
the data stored in the ServeRAID cache memory when using the write-back
setting of the write-cache mode.
You can attach internal SCSI devices to the internal Channel 1 and Channel 2
connectors. You can attach external SCSI devices to the external Channel 1 and
Channel 2 connectors. You cannot attach internal
and external SCSI devices to the
same channel. For example, you cannot attach devices to both external Channel 1
and internal Channel 1. The ServeRAID-4 controllers do not support configurations
that use both the internal and external connectors on the same channel
concurrently .
Note: The ServeRAID-4Mx controller uses the module (P/N 38L3386) containing a
lithium battery.
Internal Channel 2
Internal Channel 1
Battery for Backup Cache
External Channel 2
External Channel 1
Figure 2. ServeRAID-4Mx controller
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IBM ServeRAID: User’s Reference, Version 5.10