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Cisco Bug: CSCta84645 - CPU hog on SSM line card caused due to heartbeat failure

Last Modified

Mar 08, 2018

Products (1)

  • Cisco MDS 9000 Series Multilayer Switches

Known Affected Releases


Description (partial)

 The SSM module reloaded due to heartbeat failure with supervisor. 
 While the logs available were not sufficient to conduct a definitive RCA,
Cisco has elaborated an hypothesis on what the issue could be. By looking at
the available logs, we have reconstructed a set of events that could possibly
lead to this situation.
 The following set of events could have lead to the Module heartbeat failure:
 1.A large number of SCSI device server requests are outstanding at SANTap
(these are non Read/Write commands that need to be processed in the "control path);
 2.The zones changes or connectivity issues lead to host logouts from the
 3.Upon host logouts, ISAPI service layer tries to cleanup all the pending SCSI
device server requests and this clean up could  lead to prolonged high IPC
activity between CPP (Control path processor) and DPP (Data path processor).
 4.In this situation, the SSM CPU can become too busy to heartbeat with the
Supervisor. This will lead to HB failure, with the SSM module getting reloaded
by the supervisor.
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Bug Details Include

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  • Status
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