Author: paul.deluca

How do I restore files from my tape backup on Linux?

If you are just interested in testing the readability or listing the contents of a tape, you may perform a table of contents listing (aka readback):

tar -tzf /dev/st0

To restore a single file (CONTROL) to a temporary directory (/esupport/restore):

mkdir -p /esupport/restore
cd /esupport/restore
tar -xzvf /dev/st0 ./u2/eclipse/CONTROL

To restore an entire directory (/u2/eclipse) to it’s original location (/u2/eclipse) for a full system recovery:

Warning: As always, please exercise caution when performing system maintenance, especially when initiating processes that can potentially overwrite data.
cd /
tar -xzvf /dev/st0 ./u2/eclipse

How do I view the Linux system logs?

Nearly all Linux log files are located under the /var/log directory. You may view these log files using the text viewer or editor of your choice.

Command Line

From the command line, a common method for viewing the syslog message file is:

less /var/log/messages

GUI

View a step-by-step screencast of this process:

To view the system log files from the GUI interface:

  • Log into the GUI via any method (ie VNC, DRAC, physical console)
  • Navigate to System -> Administration -> System Log

Common Linux Logs

  • /var/log/message: general system log
  • /var/log/boot.log: boot log
  • /var/log/dmesg: kernel messages/log
  • /var/log/secure: authentication log
  • /var/log/cron: scheduled (cron) job log
  • /var/log/maillog: mail server log
  • /var/log/yum.log: software update log

 

How do I troubleshoot outbound email on Linux?

Check which MTA is being used

First, determine which mail transfer agent (MTA) you are using. Currently, Eclipse Linux servers are configured using the postfix MTA. If you are running an older system, you may be using the sendmail MTA. To determine which MTA you are running, use the following command:

ls -l /etc/alternatives/mta

If the command returns a link to “/usr/sbin/sendmail.postfix”, your system is configure to use postfix. If it returns a link to “/usr/sbin/sendmail.sendmail”, your system is configured to use sendmail.

Check the SMTP relay server

Next, verify that your system is pointing to the correct SMTP relay server.

For systems using postfix, the command is:

grep ^relayhost /etc/postfix/main.cf

For systems using sendmail, the command is:

grep ^DS /etc/mail/sendmail.cf

Check the mail logs

Once you have confirmed that the MTA is relaying to the correct SMTP server, the next step is to check the email service logs. To view the last 10 log messages and monitor the file, run:

tail -f /var/log/maillog

Check the mail queue

Once you have checked the mail logs, the next step is to check the mail queue for pending and differed email messages.

mailq

Tell Postfix to process the queue now

postqueue -f

Delete all queued mail

postsuper -d ALL

Send a test message from the command line

To send a test message from the Linux command line, use the following command (replace email@domain.com with your email address):

echo test | mail email@domain.com

If you don’t receive your email, check the logs (see above) for error messages.

Send a test message from Eclipse

In a separate Eterm or Solar window, try sending an email. If you don’t receive the message, check the logs (see above). Make note of any error messages, such as “relay denied” or “cannot connect to SMTP server.” These messages are the best source for determining which element in the email service architecture is incorrect. In our experience, most issues are related to incorrectly configured SMTP relay servers, or SMTP servers that do not allow relay from the Eclipse server.

Dell Firmware Update

There are a few different methods for updating your Dell server’s firmware, but we’ll walk you through the simplest and most reliable method that uses the server’s “Lifecycle Controller” which is also known as the “Unified Server Configurator”.

This method can be used with any operating system (i.e. Linux, Windows, VMware, etc.), because it operates outside of the OS, similar to the BIOS menus. It requires a working network connection with Internet access and rebooting the server for as long as it takes for the updates to be downloaded and installed, which is typically 15 minutes to an hour, depending on the speed of your Internet connection and how many updates need to be installed.

Here is a step-by-step guide:

  • Before rebooting the server, make note of the server’s LAN IP address, network mask, and default gateway, because you’ll need to enter these settings into the Lifecycle Controller the first time you use it.
  • Reboot the server.
  • When the BIOS menu and Dell logo appears, press the <F10> key within 10 seconds
  • Wait for the Lifecycle Controller GUI to appear
  • If this is your first time using the Lifecycle Controller to access the Internet and install updates, you’ll need to configure the network interface:
    • Click Settings in the left pane
    • Select Network Settings
    • Select Static IP address
    • Specify the IP Address, Subnet Mask, Gateway and DNS server you previously noted
    • Click Finish
  • Click Platform Update in the left pane
  • Click Launch Platform Update in the right pane
  • Select FTP Server
  • Verify that the server name is ftp.dell.com
  • Click Next
  • The Platform Update tool will now download a list of available packages for your server. This may take a while, depending on the speed of your network connection.
  • When prompted, review and select the appropriate updates to be installed
  • Click Apply
  • The system will reboot after the update process is complete. When applying more than one update, the system may need to reboot between updates. In this case, the system boots directly into USC and continues the update process. No action on your part is required when the system reboots to complete the update process.
  • When the updates are complete, the system will boot back into your operating system.

For more information, please see Updating the Platform on Dell’s website.

How do I access Dell OpenManage?

The Dell OpenManage Server Administrator allows system administrators to manage individual servers from an integrated, Web browser-based graphical user interface (GUI). OMSA is designed for system administrators to manage systems locally and remotely on a network.

You may access the Dell OpenManage web interface from any computer (replace 192.168.1.100 with your server’s LAN IP address):

  • Launch the OpenManage web interface (https://192.168.1.100:1311/)
  • Log in using your root username and password

What type of tasks can be performed using OMSA?

  • View the server’s hardware configuration
  • Check for hardware errors
  • Check for firmware updates
  • Replace or reconfigure storage

Resources: