RAID and Subsystem Architectures
Assigning Hosts to Storage
� The ratio of host ports to a single storage port
� More efficient use of storage resources
Fan-in ratio = 3:1
3 Host ports to 1 Storage port
It is unrealistic to expect each server to connect to the storage via it’s own
exclusive storage port. Fabric designs provide the ability to connect several
servers to a single storage port through one or more fabric switches. Note that
the fan-in ratio is merely the ratio of server ports to a single storage port. It is
a simple ratio that doesn’t take into account throughput calculations.
The Fan-in ratio of each storage port is determined by the zoning configuration
and is the ratio of the host ports that can connect to the storage port.