Chapter 6 High Availability; Information About High Availability - Cisco Nexus 1000V Troubleshooting Manual

High Availability
This chapter describes how to identify and resolve problems related to high availability, and includes the
following sections:
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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 if a failure occurs:
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The Cisco Nexus 1000V system is made up of the following:
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OL-31593-01
Information About High Availability, page 6-1
Problems with High Availability, page 6-2
High Availability Troubleshooting Commands, page 6-5
Redundancy—Redundancy at every aspect of the software architecture.
Isolation of processes—Isolation between software components to prevent a failure within one
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. The state and
configuration remain constantly synchronized between two Virtual Supervisor Modules (VSMs) to
provide a seamless and statefu1 switchover if a VSM failure occurs.
Virtual Ethernet Modules (VEMs) running within virtualization servers. These VEMs are
represented as modules within the VSM.
A remote management component, such as VMware vCenter Server.
One or two VSMs running within virtual machines (VMs).
C H A P T E R
Cisco Nexus 1000V Troubleshooting Guide, Release 5.2(1)SV3(1.1)
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