Quantum QX Series Setup Manual page 115

Chapter 3: Connecting Hosts
Connect the Chassis to Hosts
A failed controller can be replaced without the need to shut down the storage system.
In a dual-controller system, hosts use LUN-identifying information from both controllers to determine that up
to four paths are available to a given storage volume. Assuming MPIO software is installed, a host can use
any available data path to access a volume owned by either controller.
The path providing the best performance is through host ports on the volume's owning controller. Both
controllers share one set of 1,024 LUNs (0-1,023) for use in mapping volumes to hosts (see "ULP" in the
StorNext QXS Storage Disk Storage Management Utility Users Guide).
Dual-controller Connections to Hosts
This section provides representative illustrations of connections to hosts.
The 12-, 24-, and 48-drive systems are all similar when viewing the systems from the rear.
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The QXS-312 and QXS-324 systems have only two host ports on each controller I/O module.
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The QXS-412, QXS-424, QXS-448, QXS-456, QXS-648, and QXS-656 systems have only four host
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ports on each controller I/O module.
12-, 24-, and 48-Drive Systems
This section provides representative illustrations of 12-, 24-, and 48-drive systems connections to hosts.
Figure 90: Connecting hosts: One server and one HBA, dual path
Figure 91: Connecting hosts: Two servers and one HBA per server, dual path
QX and QXS Setup Guide
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