Dell PowerVault TL4000 - Manual (Page 53)

Zoning allows you to partition your SAN into logical groupings of devices so that
each group is isolated from the other and can only access the devices in its own
group. Two types of zoning exist: hardware zoning and software zoning. Hardware
zoning is based on physical fabric port number. Software zoning is defined with a
World Wide Node Name (WWNN) or World Wide Port Name (WWPN). While
zoning can be reconfigured without causing an outage, some zoning configurations
can become complicated. The advantage of the library's WWNN implementation is
that you can avoid the exposure of introducing zoning errors because you do not
have to change the zoning configuration if a drive needs service or replacement.
Sharing on a Storage Area Network
With Storage Area Network (SAN) components, the possibilities for connecting
multiple systems and multiple drives have increased. Not all software and systems
are designed to share drives. Before you install a drive that would allow two
systems to share it, check that the systems and their software support sharing. If
your software does not support sharing, note that Fibre Channel switches have a
zoning capability to form a SAN partition. For systems that do not cooperate, use
zoning to prevent the systems from sharing the same drive. You can remove zoned
partitions as you upgrade software and system levels.
Chapter 3. Installation Planning 3-11