VCS 5.1 SP1, released 01-Nov-2010, offers a new feature called IMF (Intelligent Monitoring Framework).

• IMF provides the following two benefits:

1) Instantaneous Notification for resource state changes (processes and mounts going offline or online), thereby strengthening the Fast-failover use-case.

2) Reduced CPU consumption by VCS agent processes when the number of resources being monitored is high, thereby providing significant
performance benefits in terms of system resource utilization.

• The IMF feature can also be used along with the CFS (Cluster Filesystem) product to provide fast failover in the range of a few seconds for mission-critical environments where every second of failover and recovery time matters.

• Without IMF, it can take upto 1 minute to detect online state changes and upto 5 minutes to detect offline state changes.

• In case you are wondering about the difference between IMF and AMF,

AMF (Asynchronous Monitoring Framework) is the kernel module that provides the asynchronous notifications to the IMF module of VCS, and

IMF (Intelligent Monitoring Framework) is the umbrella feature in VCS that can work with any 3rd-party asynchronous notification in future if required. Currently IMF uses AMF to provide the above mentioned capabilities.

• See also:

a) A screen-cast on IMF:

https://www-secure.symantec.com/connect/videos/screencast-intelligent-monitoring-framework

b) A related blog on IMF:

http://symantec.dciginc.com/2010/10/imf-sfha51sp1-proactive-monitoring.html

c) VCS User's guide (search for the keyword: IMF):

http://sfdoccentral.symantec.com/sf/5.1SP1/solaris/pdf/vcs_admin_51sp1_sol.pdf

d) A whitepaper on IMF:

https://www-secure.symantec.com/connect/articles/intelligent-monitoring-framework-imf-whitepaper

e) On a lighter note, a related quote from Einstein that elaborates on why saving 1 minute is crucial for some cases :-)

""Place your hand on a hot stove (for a minute) and it will seem to last an hour. Sit next to a beautiful lady for an hour, and it will seem to last only a minute. That is relativity." -- Einstein.

Do experiment with IMF and let us know your experiences!

Bhavin Thaker.