Configure DNS on Linux

To set or reconfigure your Linux server’s DNS server:

Open the /etc/resolv.conf configuration file:

vim /etc/resolv.conf

Set or update the name server line(s) to point to the desired DNS server(s), as shown in the example below:

nameserver 192.168.1.100
nameserver 192.168.1.101

Save the changes to apply the new DNS server configuration.

Resources:

What should I do about Red Hat Network emails?

By default, Red Hat Network (RHN) will send email notifications when errata or software updates relevant to your server are released. As with any operating system, software updates are constantly being released to fix bugs or address security concerns, and the volume of these emails may become overwhelming.

We recommend that you follow industry standard best practices and install these software updates at least once a month. For more information, please see the following articles:

If you do not wish to receive these emails, you may unsubscribe completely and manually check Red Hat’s errata page.

If you have any questions about a specific update, you may open a service request with the Linux Technical Support team.

Fix /dev/hdc Open Failed Message

The following message may appear when running Linux LVM management commands:

[root@eclipse ~]# lvs
/dev/hdc: open failed: No medium found
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
crashplan datavg -wi-ao 10.00G
eclipse datavg owi-ao 100.00G
ereports datavg owi-ao 10.00G
lvol0 datavg swi-ao 1.00G u2 21.36
lvol1 datavg swi-ao 4.28G eclipse 61.81
lvol2 datavg swi-ao 1.00G ereports 0.53
u2 datavg owi-ao 10.00G
uvtmp datavg -wi-ao 4.00G
esupport rootvg -wi-ao 10.00G
root rootvg -wi-ao 30.00G
swap rootvg -wi-ao 8.00G

You do not need to be concerned about this message, because it typically refers to a non-LVM device (ex. a DVD-ROM drive).

To get rid of the message, you can try running:

vgscan

Opening a Double-Take Support Case

If you are experiencing a problem with Double-Take, please follow this procedure to open a case with Double-Take Support:

First, gather the server logs and configuration details from both the source and destination servers. To do so, log in as root and run:

DTInfo.sh -f

This utility will gather your system information and create a compressed archive under /var/run/DT. Transfer this .tar.gz file to your workstation using your method of preference (i.e. FTP, SCP, samba, etc.).

Attach the file(s) to an email describing your problem to support@doubletake.com. You will receive an auto-response with a case number, and an engineer will respond shortly.

Double-Take Support

Overview

Double-Take is data replication software for Linux that a number of customers use for real-time replication and high-availability of their Eclipse database servers.

Support Policy

The Eclipse Systems team will provide basic troubleshooting and triage services for Double-Take replication for customers with an active Linux Technical Support subscription. If Eclipse Support suspects a system issue is the result of the Double-Take software, we will recommend that the customer escalate the case to Double-Take support. If the customer does not have a Linux Technical Support subscription, if after-hours or if non-covered maintenance is required, a quote may be provided for billable services.

Documentation

Support