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

Backbone fabric limitations

Thebackbonefab

ric is the functional element that makes the logical connection between edg e fabrics, or

between the bac

kbone fabric and an edge fabric. There are some limitations in terms of the number of

FC Routers, FC s

witches and devices that are supported in the backbone fabric.

Table 6 Backbone fabric vs. edge fabric limitations

FOS Version

FOS 5.1 FOS 5.2

Max # of device p

orts per backbone fabric

256 512

Max # of device ports per edge fabric

1000 1200

Max # of ﬁbre channel switches per backbone fabric

10 10

Max # of ﬁbre cha

nnel switches per edge fabric

26 26

NOTE:

The 2 Gb MP Rout

er does not support FC routing on any device in the backbone fabric to any edge fabric.

NOTE:

When you install the MP Router blade in the 4/256 SAN Director and create an EX_Port/VEX_Port, that

Director and the fabric attached to the Director immediately become part of the backbone fabric . That is,

all the non-router blades in the chassis become part of the backbone fabric, and the fabric containing

the Director becomes limited in scalability and port connectivity.

With the scaling limitations of the backbone fabric, it might seem intuitive to select the sm aller site to

be the backbone fabric, but if FCIP is utilized as the SAN Extension technology, the larger site (ed ge

fabric) will have the IP network as part of its fabric. Since the IP net work is the most unstable par t of this

conﬁguration, the fabric that contains the IP network(s) will see more disruptions than a fabric without the

IP network. HP recommends not including the IP network as part of the Primary site, while not limiting the

scalability of the site’s fabric(s). To do this, implement the type of conﬁguration referred to as a dedicated

backbone fabric as described in Sample topologies and conﬁgurations, page 22.

B-Series remote replication solution