Browse Prior Art Database

SCN-Server to Improve the Management of State-Change-Notification Events in a SAN or META-SAN

IP.com Disclosure Number: IPCOM000178917D
Original Publication Date: 2009-Jan-29
Included in the Prior Art Database: 2009-Jan-29
Document File: 5 page(s) / 44K

Publishing Venue

IBM

Abstract

This invention is summarized as:  when one of today's switches or routers receives (a) State Change Registration (SCR), (b) Registered State Change Notification (RSCN), or (c) detects an event for which it normally would issue a RSCN, then (d) that switch or router forwards the information to an SCN-server rather than directly to all devices and (e) then the SCN-server handles the selective notification. This inventive SCN-Server will: (1) increase performance of the entire SAN or Meta-SAN when an event occurs, because only the devices that are impacted by the event are notified. Today all devices are notified, versus the proposed selective notification. (2) Enhance the reliability of the SAN or Meta-SAN by shielding devices from intermittent link events, as intermittent link events have been known to crash end-devices. (3) Finally, this provides a centralized place where event data could be analyzed and corrective actions taken.

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SCN-Server to Improve the Management of State -Change-Notification Events in a SAN or META-SAN

A device connected in a Storage Area Network (SAN) can see activity on only one link, namely the one to which it is attached. The device must rely on an attachment-device, such as a switch or router, to provide information about other devices. This information provided is called an event in fibre channel. There is a process known in the art of Fibre Channel as State Change Notification (SCN), for devices that need or want to be notified of changes to the network environment. Examples of SCN include devices joining or leaving. Devices must sign-up (register) to be notified of the SCN. A performance problem arises when the SANs becomes large or when two or more SANs are joined together to form Meta-SANs, as it takes time for this SCN information to propagate throughout the entire SAN or Meta-SAN. If the event causing the notification is, for example, an intermittent link (a link that goes up and down every few milliseconds), then the entire SAN or Meta-SAN can become bogged down not only with the notifications, but also with the devices that were notified of the event attempting to discover the health and the availability of the device / devices which it received notification for.

This inventive SCN-Server will: (1) Increase performance of the entire SAN or Meta-SAN when an event occurs, because only the devices that are impacted by the event are notified. Today all devices are notified, versus the selective notification which is proposed. (2) Enhance the reliability of the SAN or Meta-SAN by shielding devices from intermittent link events. Intermittent link events have been known to crash end devices. (3) Finally, this provides a centralized place where event data could be analyzed and corrective actions taken.

The art of Fibre Channel already defines embedded functions inside of fibre channel switches, these function are known as servers. This invention is adding both (a) a new server called the state change notification server (SCN-server), and (b) a new state change notification registration process for switches and routers. This SCN-server will make itself known to all interested ports in the SAN using a process know in the art of fibre channel as name server registration. The type-value that is registered with the name server will be a unique value. Switches and routers that support the new registration process will recognize this new type and will perform the process known in the art of fibre channel called login. After the login process is completed, the switches and/or routers will then register to have the SCN-server process all state change notification in the future. Part of the registration process will be that the registering port will give the SCN-server a list of all ports that are currently registered with it, and then implicitly (without telling anyone) deregister the ports interna...