Service Manual

Trace Logs
In addition to the syslog buffer, Dell Networking OS buffers trace messages which are continuously
written by various Dell Networking OS software tasks to report hardware and software events and status
information.
Each trace message provides the date, time, and name of the Dell Networking OS process. All messages
are stored in a ring buffer. You can save the messages to a file either manually or automatically after
failover.
Auto Save on Crash or Rollover
Exception information for MASTER or standby units is stored in the flash:/TRACE_LOG_DIR directory. This
directory contains files that save trace information when there has been a task crash or timeout.
• On a MASTER unit, you can reach the TRACE_LOG_DIR files by FTP or by using the show file
command from the flash://TRACE_LOG_DIR directory.
• On a Standby unit, you can reach the TRACE_LOG_DIR files only by using the show file command
from the flash://TRACE_LOG_DIR directory.
NOTE: Non-management member units do not support this functionality.
Last Restart Reason
If the system restarts for some reason (automatically or manually), the show system command output
includes the reason for the restart.
The following table shows the reasons displayed in the output and their corresponding causes.
Table 87. Line Card Restart Causes and Reasons
Causes Displayed Reasons
Remote power cycle of the chassis push button reset
reload soft reset
reboot after a crash soft reset
Hardware Watchdog Timer
The hardware watchdog command automatically reboots an Dell Networking OS switch/router with a
single RPM that is unresponsive.
This is a last resort mechanism intended to prevent a manual power cycle.
Using the Show Hardware Commands
The show hardware command tree consists of commands used with the system. These commands
display information from a hardware sub-component and from hardware-based feature tables.
NOTE: Use the show hardware commands only under the guidance of the Dell Technical
Assistance Center.
The following lists the show hardware commands available as of the latest Dell Networking OS version.
1120
S-Series Debugging and Diagnostics