Reference Guide

FTOS supports graceful restart for the following protocols:
• Border gateway
• Open shortest path first
• Protocol independent multicast — sparse mode
• Intermediate system to intermediate system
Software Resiliency
During normal operations, FTOS monitors the health of both hardware and software components in the background to
identify potential failures, even before these failures manifest.
Software Component Health Monitoring
On each of the line cards and the RPM, there are a number of software components. FTOS performs a periodic health
check on each of these components by querying the status of a flag, which the corresponding component resets within
a specified time.
If any health checks on the RPM fail, the FTOS fails over to standby RPM. If any health checks on a line card fail, FTOS
resets the card to bring it back to the correct state.
System Health Monitoring
FTOS also monitors the overall health of the system.
Key parameters such as CPU utilization, free memory, and error counters (for example, CRC failures and packet loss) are
measured, and after exceeding a threshold can be used to initiate recovery mechanism.
Failure and Event Logging
Dell Networking systems provide multiple options for logging failures and events.
Trace Log
Developers interlace messages with software code to track the execution of a program.
These messages are called trace messages and are primarily used for debugging and to provide lower-level information
then event messages, which system administrators primarily use. FTOS retains executed trace messages for hardware
and software and stores them in files (logs) on the internal flash.
• NV Trace Log — contains line card bootup trace messages that FTOS never overwrites and is stored in internal
flash under the directory NVTRACE_LOG_DIR.
• Trace Log — contains trace messages related to software and hardware events, state, and errors. Trace Logs
are stored in internal flash under the directory TRACE_LOG_DIR.
• Crash Log — contains trace messages related to IPC and IRC timeouts and task crashes on line cards and is
stored under the directory CRASH_LOG_DIR.
For more information about trace logs and configuration options, refer to S-Series Debugging and Diagnostics.
Core Dumps
A core dump is the contents of RAM a program uses at the time of a software exception and is used to identify the cause
of the exception.
There are two types of core dumps: application and kernel.
• Application core dump is the contents of the memory allocated to a failed application at the time of an
exception.
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