Advanced Traffic Management Guide K/KA/KB.15.15

The following table describes how the stack reacts to the crashing switch, depending on what role
the switch had when the crash occurred. The assumption in this table is that the topology is a
resilient topology (that is, a mesh or ring).
DescriptionStacking
role
Commander
• The standby takes over as the new Commander
• A new standby is elected
• Crashing switch writes core file to local stable storage
• Crashing switch reboots and joins the stack
• Core file and crash information for this switch is available from the Commander
Standby
• A new standby is elected
• Crashing switch writes core file to local stable storage
• Crashing switch reboots and joins the stack
• Core file and crash information for this switch is available from the Commander
Member
• Crashing switch writes core file to local stable storage
• Crashing switch reboots and joins the stack
• Core file and crash information for this switch is available from the Commander
After a switch crashes, you can collect data to help HP understand why the crash occurred. The
information is a combination of crash data, crash log, and core-dump files. The show tech
command displays logs of events that happened right before the crash.
Troubleshooting an unresponsive reboot
An unresponsive reboot occurs when a member does not respond to an update packet.
Example 213 Reboot output
/* SSM_SWITCH_LOST_EVENT */
// 30 States -> Initial !Discovery !Bid for Cmdr !Become cmdr !
/* Switch Lost */{ssmIgnore ,ssmMbrRmvMbr ,ssmMbrRmvMbr ,ssmMbrRmvCmdr ,
// States -> Cmdr chas wait!Cmdr RFS start! Commander ! Cmdr Merge !
/* Switch Lost */ ssmMbrRmvCmdr ,ssmMbrRmvCmdr ,ssmMbrRmvCmdr ,ssmMbrRmvCmdr ,
// States -> Wait for chas !wait for type !stby RFS start!stby RFS sync !
/* Switch lost */ ssmMbrRmvMbr ,ssmMbrRmvMbr ,ssmMbrRmvMbr ,ssmMbrRmvMbr ,
// States -> Standby !Mbr RFS wait ! Member !Pass through !
/* Switch Lost */ ssmMbrRmvStby ,ssmMbrRmvMbr ,ssmMbrRmvMbr ,ssmIllegal },
Troubleshooting an unexpected Commander or Standby switch selection
When a switch stack is established and a boot/reboot of the stack is performed, the Commander
and Standby are selected based on the configured switch priority. There are other rules in the
election process that can override this priority.
Troubleshooting stacking 317