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This chapter introduces the basic concepts, methodology, and general troubleshooting guidelines for problems that might occur when installing, configuring, and using Cisco Nexus 1000VE.
To troubleshoot your network, follow these steps:
Step 1 Gather information that defines the specific symptoms.
Step 2 Identify all potential problems that could be causing the symptoms.
Step 3 Systematically eliminate each potential problem (from most likely to least likely) until the symptoms disappear.
We recommend that you do the following to ensure the proper operation of your networks:
This section introduces questions to ask when troubleshooting a problem with the Cisco Nexus 1000VE or connected devices. Use the answers to these questions to identify the scope of the problem and to plan a course of action.
This section includes the following topics:
By answering the questions in the following subsections, you can determine the paths that you need to follow and the components that you should investigate further.
Answer the following questions to determine the status of your installation:
To discover a network problem, follow these steps:
Step 1 Gather information on problems in your system. See the “Gathering Information” section.
Step 2 Verify the Layer 2 connectivity. See the “Verifying Layer 2 Connectivity” section.
Step 3 Verify the configuration for your end devices (storage subsystems and servers).
Step 4 Verify end-to-end connectivity. See the “Verifying Layer 3 Connectivity” section.
This section highlights the tools that are commonly used to troubleshoot problems within your network. These tools are a subset of what you might use to troubleshoot your specific problem.
Each chapter in this guide includes additional tools and commands that are specific to the symptoms and possible problems covered in that chapter.
You should also have an accurate topology of your network to help isolate problem areas.
Use the following commands and examine the outputs:
Note To use commands with the internal keyword, you must log in with the network-admin role.
Answer the following questions to verify ports:
Answer the following questions to verify Layer 2 connectivity:
Use the show vlan brief command. The status should be up.
Use the show port-profile command to check a port profile configuration.
Use the show interface brief command to check the status of a virtual Ethernet port or a physical Ethernet port.
Answer the following questions to verify Layer 3 connectivity:
Use the ping or trace commands to verify connectivity. See the following for more information:
The symptom-based troubleshooting approach provides multiple ways to diagnose and resolve problems. By using multiple entry points with links to solutions, this guide best serves users who may have identical problems that are perceived by different indicators. Search this guide in PDF form, use the index, or rely on the symptoms and diagnostics listed in each chapter as entry points to access necessary information in an efficient manner.
Using a given a set of observable symptoms on a network, it is important to be able to diagnose and correct software configuration issues and inoperable hardware components so that the problems are resolved with minimal disruption to the network. Those problems and corrective actions include the following:
The system software sends the syslog (system) messages to the console (and, optionally, to a logging server on another system) during operation. Not all messages indicate a problem with your system. Some messages are purely informational, while others might help diagnose problems with links, internal hardware, or the system software.
This section contains the following topics:
Message-text is a text string that describes the condition. This portion of the message might contain detailed information about the event, including terminal port numbers, network addresses, or addresses that correspond to locations in the system memory address space. Because the information in these variable fields changes from message to message, it is represented here by short strings enclosed in square brackets. A decimal number, for example, is represented as [dec].
Use this string to find the matching system message in the Cisco NX-OS System Messages Reference System Messages Reference.
Each system message is followed by an explanation and recommended action. The action may be as simple as “No action required.” It may involve a fix or a recommendation to contact technical support as shown in the following example:Error Message 2009 Apr 29 14:57:23 switch %MODULE-5-MOD_OK: Module 3 is online (serial:)
next_gen_fcs_ip_38# show dc hosts vse
VSE UUID : 42193D34-FBB0-A6E9-4AAE-C4BC3043C013
Explanation VSE module inserted successfully on slot 3.
Recommended Action None. This is an information message. Use the show module command to verify the module in slot 3.
The syslog facility allows the Cisco Nexus 1000VE to send a copy of the message log to a host for more permanent storage. This feature can be useful if the logs need to be examined over a long period of time or when the Cisco Nexus 1000VE is not accessible.
This example demonstrates how to configure a Cisco Nexus 1000VE to use the syslog facility on a Solaris platform. Although a Solaris host is being used, the syslog configuration on all UNIX and Linux systems is very similar.
Syslog uses the concept of a facility to determine how it should be handled on the syslog server (the Solaris system in this example), and the message severity. Therefore, different message severities can be handled differently by the syslog server. They could be logged to different files or emailed to a particular user. Specifying a severity determines that all messages of that level and greater severity (lower number) will be acted upon.
Note The Cisco Nexus 1000VE messages should be logged to a different file from the standard syslog file so that they cannot be confused with other non-Cisco syslog messages. The logfile should not be located on the / file system, to prevent log messages from filling up the / file system.
Syslog Client: switch1
Syslog Server: 172.22.36.211 (Solaris)
Syslog facility: local1
Syslog severity: notifications (level 5, the default)
File to log Cisco Nexus 1000VE messages to: /var/adm/nxos_logs
To configure a syslog server, follow these steps:
Step 1 Configure the Cisco Nexus 1000VE.
switch# config terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch (config)# logging server 192.0.2.1 6 facility local1
switch#show logging server
Step 2 Configure the syslog server.
a. Modify /etc/syslog.conf to handle local1 messages. For Solaris, t at least one tab needs to be between the facility.severity and the action (/var/adm/nxos_logs).
d. Verify that the syslog has started.
Step 3 Test the syslog server by creating an event in the Cisco Nexus 1000VE. In this case, port e1/2 was bounced and the following was listed on the syslog server. Notice that the IP address of the switch is listed in brackets.
The Cisco Nexus 1000VE generates many types of system messages on the switch and sends them to a syslog server. These messages can be viewed to determine what events might have led up to the current problem condition that you are facing.
Use the following commands to access and view logs in the Cisco Nexus 1000VE.
switch#show logging ?
Example 1-1 shows an example of the show logging command output.
Example 1-1 show logging Command
switch#show logging server
For additional information, visit one of the following support communities:
If you are unable to solve a problem after using the troubleshooting suggestions in this guide, contact a customer service representative for assistance and further instructions. Before you call, have the following information ready to help your service provider assist you as quickly as possible:
If you purchased the Cisco Nexus 1000VE and support contract from Cisco, contact Cisco for Cisco Nexus 1000VE support. Cisco provides Layer 1, Layer 2, and Layer 3 support.
After you have collected this information, see the “Obtaining Documentation and Submitting a Service Request” section.
For more information on the steps to take before calling Technical Support, see the “Gathering Information” section.