Issue:
Changes to the Fibre Channel SAN fabric creates frame drops within a video editing environment.
Cause:
Any changes to the Fibre Channel SAN fabric result in Registered State Change Notification, otherwise known as an RSCN.
RSCNs are part of the Fibre Channel specification and all devices are required to process the change information. Changes to the SAN could include a server crashing or coming online, additional storage attached, changes in zoning or adding another switch in the Fibre Channel fabric. When a change happens, RSCN will alert all Fibre Channel devices that the topology changed, and each device will pause to update their configuration information.
Solution:
Use a Fibre Channel Switch that can intercept and manage the RSCNs
QLogic SANbox and SANbox2 Switches have I/O StreamGuard to manage the RSCNs.
The following article from QLogic provides more detail regarding RSCNs and how they can be managed for optimal performance.
I/O StreamGuard - Implementation and Uses:
http://www.coolspirit.co.uk/uploadfiles/QLogic%20FCS%20IO%20Streamguard.pdf
Apple preferred configurations:
Preferred Configuration Scripts:
http://support.apple.com/kb/HT1200
Qlogic Switch Configuration Info:
http://support.apple.com/kb/HT1084
