Chapter 4. Troubleshooting
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## Chapter 4. Troubleshooting

This chapter describes what to do when your load-balancing network connection has problems. The chapter describes the following topics:

- “Initial Remedies”

- “Connection Has Not Been Functional Since Last Boot”

- “Connection Has Been Functional in the Recent Past”

- “High Rate of Packet Loss Occurs”

- “System Cannot Communicate With Other Systems”

- “System Does Not Load Miniroot or Boot From the Network”

## Initial Remedies

When you experience difficulty with the load-balancing network connection at a particular system, you can do the following:

1. Check the physical connections at the system; consult the owner's guides for the equipment.

2. Search or read the `/var/adm/SYSLOG` file and console window for error messages. If you find any Network Load Balancing Software driver messages, read about them in Appendix B.

3. Use `lbstat -C` to evaluate the state of the load-balancing device(s) on the system. In particular, the state for each Ethernet port attached to the load-balancing device should be LINK_GOOD. If a port does not show this status, check its cabling.

## Connection Has Not Been Functional Since Last Boot

If the Network Load Balancing Software connection has not been working since the last time the system was booted, or if this is an initial installation of a Network Load Balancing Software product, one or more of the following could be occurring:

- The operating system has not been rebuilt to include the driver.

- The Network Load Balancing Software interface or the aggregated Ethernets have not been configured properly.

Follow the instructions below to determine the cause of the problem:

1. Verify that the installed IRIX operating system and Network Load Balancing Software software are the correct versions by doing the following:

   - Determine the correct versions of IRIX and of the Network Load Balancing Software. The Network Load Balancing Software release notes indicate the correct IRIX and Network Load Balancing Software versions.

   - Use the `versions` command to display the installed release identifications:

         % /usr/sbin/versions eoe.sw.base
         eoe1 date Execution Only Environment 1, 6.5

     If the version is not correct, install the correct version.

     | Note: The `eoe.sw.base` subsystem must be 6.5 or later for the Network Load Balancing Software to work.

2. View `/etc/config/nlb.options`; use `lbconfig` to check for Ethernets attached to the load-balancing devices.

3. Use `netstat`, as shown below, to display the currently configured network interfaces.

       % /usr/etc/netstat -in

   Figure 4-1 shows example output.

   Figure 4-1. Displaying Available Interfaces With netstat -in

   If the Network Load Balancing Software interface is not displayed, continue to the next step. If the interface is displayed, but the configuration is incorrect, follow the instructions in Chapter 2 to reconfigure it.

4. Verify the Network Load Balancing Software entries in the `/etc/config/netif.options` file. For example, check the spelling of the network interface.

5. Use `/etc/autoconfig` to rebuild the operating system to include the Network Load Balancing Software driver. Reboot the system to start using the new operating system.

6. Invoke `netstat -in` again. If the Network Load Balancing Software interface is still missing, contact your service provider.

## Connection Has Been Functional in the Recent Past

Follow these steps to resolve the problem:

1. Ensure that the system is using the operating system that was built most recently. Use `/etc/autoconfig` to rebuild the operating system, and then reboot to start using it.

2. Watch the messages on the terminal during restart to verify that each network interface is configured correctly. The messages should look similar to these examples:

       Configuring lb0 as sys3
       Configuring ec0 as gate-sys3

   If the load-balancing driver is not mentioned on the terminal during startup, there is a problem with the software.

3. Use `netstat` to display the currently configured network interfaces.

       % /usr/etc/netstat -in

   If the interface is displayed, but the configuration is incorrect, follow the instructions in Chapter 2 to reconfigure it.

   The `/etc/config/netif.options` file may have an incorrect entry (for example, a misspelled network interface); verify all file contents carefully.

If the interface does not display, the software may be dysfunctional. Contact your service provider.

## High Rate of Packet Loss Occurs

If high packet loss is displayed by the `ping` command, follow these steps:

1. Confirm that the source and destination IP addresses are on the same subnet. If there was any doubt that they are, enter `ping -R`, or `traceroute` to check the route. (For information on the latter command, see its manpage, `traceroute(1M)`.)

2. If the source and destination IP addresses are attached to the same switch and `ping` still drops packets:

   - Enter `netstat -C` on the source and destination systems.

   - Enter `ping -f` on the source and destination systems to make the problem more obvious.

   In the `netstat` output, inspect the packet counts and indications of input errors or output errors while `ping` is running.

   If the output shows (approximately) one packet dropped per second, check for defective hardware. Make sure all cables are seated properly.

3. If the `netstat` output shows no such errors:

   - Consult the documentation for the switch and its management software.

   - Use statistics tools specific to the protocol you are using (IP, UDP, TCP/IP) to determine drops.

   - Check for defective hardware such as switch ports and problems with the cabling.

## System Cannot Communicate With Other Systems

If `ping` does not elicit a response from any system, the `/etc/hosts` and `/etc/config/netif.options` files may not have been set up properly. For example, the files may be configuring the Network Load Balancing Software interface with the Ethernet IP address.

Verify that the IP (inet) addresses for all network interfaces are correct. To display the currently configured IP addresses, enter

    % /usr/etc/netstat -in

If the addresses are not correct, follow the instructions in Chapter 2 to reconfigure the Network Load Balancing Software.

If the problem persists, identify other problems, as described in “Verifying the Network Load Balancing Software Connection”.

## System Does Not Load Miniroot or Boot From the Network

Silicon Graphics workstations and servers are capable of loading a small-sized version of the operating system (the miniroot) and booting themselves over the network; however, they are capable of doing this only over Ethernet local area networks (they cannot boot over Network Load Balancing Software networks) that are configured as the primary network interface.

If your system is unable to load the miniroot (or boot over the network), verify that its primary network interface is an Ethernet connection by following these instructions:

1. Restart the system from the System Maintenance menu. Do not rebuild the operating system during this restart.

2. Log on and open a shell window.

3. Use these commands to display the ordering of the network interfaces:

       % /usr/etc/netstat -i
       <primary interface>
       <secondary interface>
       ...

4. If the primary interface is an Ethernet (for example, `ef0` or `et0`), the Ethernet network connection may be dysfunctional. See IRIX Admin: Networking and Mail for information about Ethernet network connections.

   If the primary interface is not an Ethernet, go to step 5.

5. Configure an Ethernet connection as the primary interface.

6. Reboot the system. When the system is up and running, it should be able to load the miniroot over the network and boot from it.

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Chapter 3. Performance Tuning |  | Appendix A. Validated Ethernet Switches