Reference Guide
Debugging and Diagnostics
This chapter describes the debugging and diagnostics tasks you can perform on the switch.
Topics:
• Offline Diagnostics
• TRACE Logs
• Last Restart Reason
• show hardware Commands
• Environmental Monitoring
• Troubleshooting Packet Loss
• Accessing Application Core Dumps
• Mini Core Dumps
• Full Kernel Core Dumps
• Enabling TCP Dumps
Offline Diagnostics
The offline diagnostics test suite is useful for isolating faults and debugging hardware.
The diagnostic tests are grouped into three levels:
● Level 0 — Level 0 diagnostics check for the presence of various components and perform essential path verifications. In
addition, they verify the identification registers of the components on the board.
● Level 1 — A smaller set of diagnostic tests. Level 1 diagnostics perform status/self-test for all the components on the board
and test their registers for appropriate values. In addition, they perform extensive tests on memory devices (for example,
SDRAM, flash, NVRAM, or EEPROM) wherever possible.
● Level 2 — The full set of diagnostic tests. Level 2 diagnostics are used primarily for on-board Loopback tests and more
extensive component diagnostics. Various components on the board are put into Loopback mode and test packets are
transmitted through those components. These diagnostics also perform snake tests using VLAN configurations.
Important Points to Remember
● Diagnostics only test connectivity, not the entire data path.
● Diagnostic results are stored on the flash of the switch on which you performed the diagnostics.
Running Offline Diagnostics
To run offline diagnostics:
1. Place the switch in offline mode.
EXEC Privilege mode
offline system
NOTE:
When the diagnostic tests complete on all Z9500 CPUs, you are prompted to reload the system. The system
requires a full reboot to resume normal operation.
A warning message displays after you enter the offline system command. Type yes to proceed:
Warning - offline of system will bring down all the protocols and
the system will be operationally down, except for running Diagnostics.
The "reload" command is required for normal operation after the offline command is
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