Dell Compellent Series 40 - Manual (Page 58)

52 Storage Center System Setup Guide
Virtual Storage and Virtual Ports
Virtual Port Mode
By default, a single virtual port resides on each Front End Physical port. If a port or
controller fails, Storage Center moves the virtual port to another Physical port within the
Fault Domain. By definition, Physical ports cannot be moved. Because volumes are
mapped to servers via virtual ports, failover of a Virtual port to a second Physical port
ensures the integrity of data via the Fault Domain.
Figure 46 illustrates Fault Domains of each supported transport type (iSCSI and FC). If a
port fails, service moves to a port in the same Fault Domain, on the same controller. At a
minimum, make sure there are two ports in the same Fault Domain on the same controller.
All ports within a Fault Domain read/write data, thus doubling available Front End ports.
Figure 46. Virtual Ports Diagram
Figure 46 illustrates the following:
• iSCSI ports from each controller comprise two Fault Domains. Four green ports connect
to Network 1. Four purple ports connect to Network 2.
• FC ports from each controller comprise two other Fault Domains. Four red ports connect
to FC Switch 1. Four blue ports connect to FC Switch 2.
• Because each primary FC port does not require a reserved FC port, ports can be freed
to connect to back end enclosures.
A Preferred Physical Port identifies the primary location of a virtual port. If a virtual port is
connected to a Physical port that is not its Preferred Physical Port, the Physical port is
designated Not Preferred and controllers are considered unbalanced. The Rebalance
Local Port command returns each virtual port to its Preferred Physical Port location.
A control port is created for each iSCSI Fault Domain. iSCSI Servers connect to the
Compellent Storage Center via the control port. The control port redirects the connection to
the appropriate virtual port.