User`s guide

206 Implementing an Open IBM SAN
Zoning methods
INRANGE provides both these types of zoning:
򐂰 Hard zoning
򐂰 Name server zoning (often called soft zoning)
Hard zoning makes it impossible to have I/O between different hard zones,
whereas with soft zoning, one port could easily be assigned to any other port in
the fabric.
However, both kinds of zoning are port related. It is the director’s port that is
referred to in both methods. At this time, a WWPN based zoning referring to the
attached server or storage ports is not available. This will become available in
the second half of 2001.
Both kinds of zoning are explained in 3.4.6, “Defining name server zones” on
page 252.
The consequences are different for tape and for disk attachments. Most disk
servers use LUN masking. This prevents the volumes from being used by
another server other than the assigned one. So in an FC/9000 and ESS
environment, unplugging the ESS cables from one zone and putting them into
another zone, it will not be possible to access the ESS volume from servers that
have not been associated with this storage.
However, this is different with tape. Tape drives normally do not support LUN
masking. Therefore, the only access control is provided by the zoning methods of
the director. Using the director-port based zoning concept, this tape drive could
potentially be accessed by other hosts just by changing the cabling.
To limit the physical access to the director, consider some of these possibilities:
򐂰 Use the INRANGE cabinet with locked doors to prevent access to the cabling.
򐂰 Also limit the access to any patch panels used in your SAN infrastructure.
򐂰 Use access control methods for the datacenter facility.
Consequences of leaving the fabric unzoned
When the fabric with all directors and/or switches is in initial mode, then no name
server zone is defined at all.
By default, all ports are in one hard zone called the default zone. Note that you
always have to have all physical ports included in a hard zone. However, when
using only name server table based zoning, you can just leave the hard zone
setting as they are by default.