HP StorageWorks B-Series Remote Replication Solution Best Practices Guide (5697-6731, June 2007)

3 Solution s etup overview

Solution conﬁguration concepts

B-Series ﬁbre channel-to-ﬁbre channel routing

FC-to-FC Routing is a technology that logically connects physically separate fabrics (SAN islands) to

enable selective shared access to resources from any fabric, with the beneﬁts of administration and

fault isolat

ion of separately managed fabrics. FC routing does not merge the fabrics, so the issues

associated w

ith merging fabrics, such as Domain ID overlaps and Zoning conﬂicts, do not apply. FC

routing provides selective device connectivity via Logical Storage Area N etworks (LSANs), but p revents

Fibre Channel services (e.g. FC Name Server) from propagating between fabrics. As a result, disruptions

to a fabric are contained, and have less impact than would be the case without FC routing. Another

beneﬁt of FC routing is that it allows each fabric to maintain independent administration, thus preventing

fabric administrator errors from propagating between fabrics in addition to isolating failures in hardware

or software. For example, if an a dministrator at one site accidentally deletes the fabric-wide zoning

conﬁguration, with FC routing in place, this will not propagate to other sites.

Another advantage FC routing provides is that the scalability of one edge fabric does not affect

another; fabric reconﬁgurations do not propagate between edge fabrics, and faults in fabric services

are contained. Furthermore, if FC routing is used with leg a cy switches, the overall network size can

vastly exceed the hardware and software capabilities of those switches. None of these features are true

with one large merged fabric.

There are a number of new terms associated with the FC routing that need to be deﬁned in order to

understand the design concepts of using FC routing between FC SANs.

Meta SANs

When FC switches are connected directly to each other via Inter-Switch Links (ISLs), they form a fabric. A

dual redundant SAN is an unconnected pair of redundantly conﬁgured fabrics.

When multiple fabrics are connected through a FC-to-FC router, they form a different kind of SAN. The

resulting FC-routed Storage Area Net work is a level above the common deﬁnition of SAN and is called

a Meta SAN, or sometimes a routed FC SAN.

At a minimum, a Meta SAN consists of one and only one backbone fabric and one or more edge fabrics,

and the backbone fabric must contain at least one MP Router. For high availability, you may conﬁgure a

dual redundant Meta SAN just as you would conﬁgure a dual redundant SAN.

B-Series remote replication solution