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3-2
EMCFib re Channel Storage-System Configuration Planning
Planning File Systems and LUNs with Shared Switched Storage
Dual Paths to LUNs
A shared storage system includes two or more servers, one or two
Fibre Channel switches, and one or more storage systems, each with
two SPs and Access Logix software.
With shared storage, there are two paths to each LUN in the storage
system. The storage-system software, using optional software called
Application Transparent Failover (ATF), can automatically switch to
the other path if a device (such as a host-bus adapter or cable) fails.
With unshared storage, if the server has two adapters and the storage
system has two SPs, ATF software is available as an option. With two
adapters and two SPs, ATF can perform the same function as with
shared systems: automatically switch to the other path if a device
(such as host bus adapter or cable) fails.