HP StorageWorks MSA 2.8 SAN Switch - Manual (Page 44)

Zoning Concepts
44 Zoning Version 3.1.x/4.1.x User Guide
Rule 7 Zone changes in a production fabric can result in a disruption of I/O
under conditions where an RSCN is issued as a result of a zone
change and the host bus adapter (HBA) is unable to process the
RSCN quickly enough. Though RSCNs are a normal part of a
functioning SAN, the pause in I/O may not be acceptable. For these
reasons, it is recommended to do zone changes only if the resulting
behavior is known and acceptable. Changing HBA drivers can
rectify the situation.
Rule 8 After changing or enabling a zone configuration, the user should
confirm that nodes and storage are able to see and access one
another. Depending on the platform, the user may need to reboot
one or more nodes in the fabric with the new changes to the zone.