nStor NexStor 4200F Series, User Manual

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Chapter 2 - Topologies and Operating Modes
Duplex Mode
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Duplex Mode
The duplex operating mode is a dual RAID controller, active-active storage
solution that provides a minimum level redundancy solution through the most
robust redundant solution. It supports both Multi-Port and Multiple-TID failover
topologies.
NOTE: There are three other topologies included in the controller’s failover
topology parameters that are not supported: Inactive Port, Clustering
Failover, and Master-Slave.
In the Multi-Port failover topology, all host ports are active and connected to
individual fibre loops. This topology requires alternate path software since it does
not support transparent failover and failback operations.
In the Multiple-TID (Target ID) failover topology, the controllers’ host ports have
the ability to function as multiple target ports on a single arbitrated loop. During
failover, the surviving controller enables a virtual port, impersonating the ports
from the failed controller. The Multi-TID topology role becomes an important
consideration in a duplex environment when transparent failover is required.
The following topology configurations are available for the Duplex mode:
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Multi-TID Single Host Single Connection
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Multi-TID Single Host Dual Connection
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Multi-TID Dual Host System-Quad Connection
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Multi-Port Dual Host System-Quad Connection
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Multi-TID SAN Attach Single Switch Connection
■
Multi-TID SAN Attach Dual Switch Connection
4200F.book Page 26 Thursday, January 23, 2003 2:47 PM