Deployment Guide
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Connect the Front-End Cabling
Front-end cabling refers to the connections between the storage system and external devices such as host servers or another
Storage Center.
Front‐end connections can be made using Fibre Channel, iSCSI, or SAS interfaces. Dell recommends connecting the storage system
to host servers using the most redundant option available.
Types of Redundancy for Front-End Connections
Front-end redundancy is achieved by eliminating single points of failure that could cause a server to lose connectivity to the Storage
Center
.
Depending on how the Storage Center is cabled and configured, the following types of redundancy are available.
Table 1. Redundancy and Failover Behavior
Redundancy Failover Behavior
Asymmetric Logical Unit
Access (ALUA)
If a storage controller becomes unavailable, all the standby paths on the other storage controller
become active.
Port redundancy If a single port becomes unavailable, the port can move to another available port in the same fault
domain.
Storage controller redundancy If a storage controller becomes unavailable, the ports on the offline storage controller can move
to the available storage controller.
Path redundancy When multiple paths are available from a server to a storage system, a server configured for
multipath I/O (MPIO) can use multiple paths for I/O. If a path becomes unavailable, the server
continues to use the remaining available paths.
Port Redundancy
To allow for port redundancy, two front-end ports on a storage controller must be connected to the same switch or server.
Fault domains group front-end ports that are connected to the same network. Ports that belong to the same fault domain can fail
over to each other because they have the same connectivity.
If a port becomes unavailable because it is disconnected or a hardware failure has occurred, the port moves over to another port in
the same fault domain.
Storage Controller Redundancy
To allow for storage controller redundancy, a front-end port on each storage controller must be connected to the same switch or
server.
If a storage controller becomes unavailable, the front-end ports on the offline storage controller move over to the ports (in the same
fault domain) on the available storage controller.
Connect the Front-End Cabling
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