To find out the WWN port name of a HBA under Linux, reading the port_name file is sufficient - e.g. for all HBAs: 1$ cat /sys/class/scsi_host/host*/device/fc_host/host*/port_name 20x2002f6dc44b8e2b6 30x2001f6dc44b8e2b6

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I'm currently working on a blog post series about Foreman, Katello and Red Hat Satellite 6. Here's the link collection for beginners: "Introduction and installation" (also published on Pro-Linux [button size="xsmall" color="red"]german[/button]) "Products, Repositories and Content …

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Recently, I had to remove a SAN LUN on a physical Enterprise Linux system. The first step was to alter the multipath service configuration file (/etc/multipath.conf) and make the daemon reload its configuration: 1# vi /etc/multipath.conf 2... 3ESC ZZ 4 5# service multipathd reload Afterwards, the device was removed …

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Changed Block Tracking (CBT) enables creating incremental backups of virtual machines. In comparison with conventional VM backups, guest hard drives are synchronized. Using CBT, the hypervisor detects changed blocks and the backup software will only store these blocks. Unfortunately these are some vSphere and backup …

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Recently I found out that Red Hat Identity Management (IdM) and FreeIPA tend to forgot their global DNS configuration after some upgrades. In my case, the global DNS forwarder configuration was dropped forcing external lookups to fail: 1$ ipa dnsconfig-show 2--------------------------------- 3Global DNS configuration …

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Wordpress updates, themes and plugins can be installed very comfortable in the backend - unfortunately it is still required to specify FTP or FTPS connection information. Depending on your personal preferences or security policy FTP is often not an option - e.g. when you're maintaining a central directory for SSH users …

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During a fresh CentOS installation recently I had the problem that a system's network connection was not working reliably. Sometimes pings were possible, sometimes not. After it was possible to elimiate the firewall as commonly root cause, it turned out that the network connectivity was only working if the console is …

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The middle mouse button offers extended functionality in the most software - e.g. it can be used in web browsers to open or close tabs. When using the integrated trackpad of a MacBook or the Apple Magic Mouse this will not work due to missing mouse buttons. To enable this functionality under OS X there is a free …

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System administrators know requirements like this - a dedicated server needs to be deployed for a new application. In order to enable owners to maintain their application they need permissions to modify relevant configuration files. In this scenario, sudo rules are often configured in a way to enable file modifications …

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If you want to combine multiple terminal sessions on one window, multiplexers such as tmux or GNU Screen are useful tools. I have been using screen for 10 years with the following configuration: 1$ cat ~/.screenrc 2# F7+F8 for tab switching 3bindkey -k k7 prev 4bindkey -k k8 next 5 6# disable welcome 7startup_message …

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