High Availability; Information About High Availability - Cisco Nexus 1000V Troubleshooting Manual

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High Availability

This chapter describes how to identify and resolve problems related to High Availability.
This chapter includes the following sections:
• Information About High Availability, page 6-1
• Problems with High Availability, page 6-2
• High Availability Troubleshooting Commands, page 6-5

Information About High Availability

The purpose of High Availability (HA) is to limit the impact of failures—both hardware and software—
within a system. The Cisco NX-OS operating system is designed for high availability at the network,
system, and service levels.
The following Cisco NX-OS features minimize or prevent traffic disruption in the event of a failure:
Redundancy— redundancy at every aspect of the software architecture.
•
Isolation of processes— isolation between software components to prevent a failure within one
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process disrupting other processes.
Restartability—Most system functions and services are isolated so that they can be restarted
•
independently after a failure while other services continue to run. In addition, most system services
can perform stateful restarts, which allow the service to resume operations transparently to other
services.
Supervisor stateful switchover— Active/standby dual supervisor configuration. State and
•
configuration remain constantly synchronized between two Virtual Supervisor Modules (VSMs) to
provide seamless and statefu1 switchover in the event of a VSM failure.
The Cisco Nexus 1000V system is made up of the following:
Virtual Ethernet Modules (VEMs) running within virtualization servers. These are represented as
•
modules within the VSM.
• A remote management component, for example. VMware vCenter Server.
• One or two VSMs running within Virtual Machines (VMs)
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C H A P T E R
Cisco Nexus 1000V Troubleshooting Guide, Release 4.2(1)SV2(2.1)
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