Servers – Windows and Linux
Posts by Lyle
Creating a Symbolic Link
0Symbolic links or soft links is a special type of file that contains a reference to a file or directory in the form of an absolute or relative path. In other words it’s like a shortcut for those Windows users out there.
I’ll be using CentOS for this tutorial but it’s the same on all distributions of Linux and Unix. (more…)
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Channel Bonding on CentOS 6.2
0Channel bonding is also known as Network Bonding. It involves pairing network devices to increase throughput or load balance. Cases that you’d need something like this would be on a server with a high network traffic. Mostly I’ve had this problem with monitoring servers that are running Cacti and Nagios.
Also the devices don’t have to be the same brand.
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Find the Linux Distribution Name and Version
0How do I find my Linux distribution name and version? I often find myself asking that question because we have multiple environments with a lot of VM’s running. It’s becomes a lot to keep track of if you haven’t completed the documentation for the environment yet.
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Setup BIND DNS Server with Webmin on CentOS 6.2
0For this setup I will be using the following:
CentOS 6.2
Yum (Yellowdog Updater, Modified)
IP Address: 192.168.0.10
You’d generally use the following config for an office or home network. I’ve setup a few of these BIND servers for office networks and also in the Amazon cloud platform. You don’t need the Webmin interface to work with BIND but I’ve found that making quick changes using Webmin is easier.
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Send Commands via SSH
0Just a little bit of knowledge that every Linux Administrator should know. You can indeed send SSH commands to a remote system without logging in, granted you have an account on that machine and know the password.
Below you can see a command that I sent to a backup server to stop the Bacula File Daemon service.
[lyle@localhost ~]$ ssh root@backup01 'service bacula-fd stop' bacula-fd is stopped
As you can you just need to add the command in a single quote. After pressing enter to send the command you will be prompted for the password. You will then receive the output of the command.
Another handy option to add is -t, this will keep the connection open so that you can interact with a screen-based program like top. It would be very useful if editing a file using vi. (more…)
Dell PowerEdge R720 and CentOS 6 Installation
0I ran into a problem installing CentOS 6 on a Dell PowerEdge R720. The problem being, the RAID controller was too new so there were no drivers on the installation media.
The error that came up:
No Drives Found
An error occurred – no valid devices were found on which to create new file systems. Please check your hardware for the cause of this problem.
This particular batch of servers have the PERC H710 Mini RAID Controller. 300GB 15000RPM SAS drives installed in it.
It could be a different RAID controller in your server, so this will only work on the PERC H710 series. (more…)
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Redirection operators
1Have you ever run a script and it goes too fast to see the output or there’s too much output and you can’t scroll back far enough. Then you need redirection.
The one I use the most would be to direct standard output to a text file for reference later. (more…)
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The du command
0I recently passed the LPIC 101 exam so I thought I’d share a little bit of what comes in the first exam. The two things in this post that were part of the exam would be du with the –max-depth option.
The du or disk usage command will estimate the amount of space being used by the files and directories within the current directory. The individual file sizes will just be a cumulative size shown with the directory as a whole.
If you’d like the full write-up about the du command then you could check the manual pages.
[root@localhost:/home]# man du
I’ll list the most useful options to use with the du command in this post.
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Retrieve your Dell Service Tag using command prompt and Linux CLI
01 year ago
It’s been a long time since I’ve posted anything on the system admin front, so here we go.
I work with Dell a lot and dealing with their technical support is the least favourite part of my day when something goes wrong. You always need to supply them with a service tag number, but what if you need a part for a server that’s located in an internet data centre? Most times I run into this exact problem. Other times, I don’t feel like getting up and going to have a look.
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Google halts Android 4.0.3 update
0Google has put a halt on the release of the latest update for the Nexus S. There have been reports of a decrease in battery life. I have also experienced this since updating my Nexus S over the weekend. Usually after a day of moderate to high usage I’d get home with about 60% battery life, now for the past 3 working days I’ve noticed the battery life to be around 30%-40% when getting home after work. (more…)
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