Dell S4820T, Configuration Manual

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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.
• Kernel core dump is the central component of an operating system that manages system processors
and memory allocation and makes these facilities available to applications. A kernel core dump is the
contents of the memory in use by the kernel at the time of an exception.
System Log
Event messages provide system administrators diagnostics and auditing information.
Dell Networking OS sends event messages to the internal buffer, all terminal lines, the console, and
optionally to a syslog server. For more information about event messages and configurable options, refer
to
Management .
Hot-Lock Behavior
Dell Networking OS hot-lock features allow you to append and delete their corresponding content
addressable memory (CAM) entries dynamically without disrupting traffic. Existing entries are simply
shuffled to accommodate new entries.
Hot-Lock IP ACLs allows you to append rules to and delete rules from an access control list (ACL) that is
already written to CAM. This behavior is enabled by default and is available for both standard and
extended ACLs on ingress and egress. For information about configuring ACLs, refer to
Access Control
Lists (ACLs) .
Process Restartability
Process restartability is an extension to the Dell Networking OS high availability system component that
enables application processes and system protocol tasks to be restarted.
This extension increases system reliability and uptime by attempting to restart the crashed process on
primary RPM before executing the failover procedure as a last resort.
Currently, if a software exception occurs, Dell Networking OS executes a failover procedure. In a single-
RPM system, the system generates a coredump and reboots; in a dual-RPM system, the system generates
a coredump and fails over to the standby RPM.
With a system reload, the system must read and apply the entire startup-config file, which might take
some time if the startup-config is large. Restarting a process saves time because only a portion of the
configuration related to the crashed process is read and reapplied.
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High Availability (HA)