Dell PowerVault MD3260 - Manual (Page 8)

You choose the data configuration based on:
• Number of hosts required
• Level of data redundancy required
Redundant And Non-Redundant Configurations
Non-redundant configurations are configurations that provide only a single data path from a host to the storage array.
This type of configuration is only recommended for non-critical data storage. Path failure from a failed or removed cable,
a failed HBA, or a failed or removed RAID controller module results in loss of host access to storage on the storage
array.
Redundancy is established by installing separate data paths between the host and the storage array, in which each path
is to one of the two RAID controller modules installed in the storage array. Redundancy protects the host from losing
access to data in the event of path failure, because both RAID controller modules can access all the disks in the storage
array.
Dual Controller Configurations
The following figures show two and four hosts, each connected to two RAID controller modules. Since each host has
redundant paths, loss of a single path would still allow access to the storage array through the alternate path.
Figure 1. Two Hosts Connected to Two Controllers
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