San Zoning Considerations; Ds400 Single Controller Example Configurations - IBM TotalStorage DS300 Best Practices Manual

8.1 SAN zoning considerations

Fibre Channel switches allow the configuration of zoning. Zones are used to
create sets of devices which should be able to communicate with each other
through a fabric. A device is either an initiator such as an HBA or a target such as
a disk controller or tape drive.
With single HBA zoning, each zone contains exactly one initiator (HBA), but can
contain multiple targets. If an HBA should connect to both disk and tape devices,
we suggest you create two zones for this HBA (one containing the HBA and the
disk devices, and the other one containing the HBA and the tape devices). This
leads to at least as many zones as HBAs exist in the SAN. But in this way, each
zone contains only a limited number of members.
Whenever a device is added to or removed from a fabric, a so-called
State Change Notification
to a fabric receive this RSCN. Each device then queries the nameserver of the
fabric to get updated information about the membership in the fabric. This also
occurs if the notified device does not care about the device which caused the
RSCN.
In a SAN, initiators only communicate with targets. Initiators do not communicate
with each other, as targets also do not communicate with each other. So initiators
have no use for RSCNs caused by other initiators. The same applies for targets.
Single HBA zoning helps to reduce the impact of adding or removing devices in a
SAN only to those members which are in the same zone. It fences off different
operating systems to reduce challenges related to operating system and device
driver interoperability. It also can minimize unwanted interactions between
devices and facilitate fault isolation.
More information about zoning can be found for example in the whitepaper
Zoning implementation strategies for Brocade SAN switches, available from:
http://www.brocade.com/san/white_papers/pdf/Zoning_Imp_WP_00.pdf

8.2 DS400 single controller example configurations

In this section we describe two example configurations for the DS400 single
controller model.
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IBM TotalStorage DS300 and DS400 Best Practices Guide
(RSCN) occurs. Without zoning, all devices attached
Registered