wekadesign

I’ve been looking around for some easy and open-source ways to handle database replication for a handful of small but important MySQL databases. A few options were viable but usually included too many config changes for things like creating a new database. DRDB on a Linux server seems to be one of the fastest and easiest methods to handle database synchronisation for DR purposes, so this is the subject of this post. The content is a combination of two main sources from Mark Schoonover and the Ubuntu server guide and the gotchas I found along the way.

This post will show you how to create two MySQL servers that automatically replicate all their databases using DRBD. With Heartbeat installed on a third machine you’ll have basic fail over protection as well (we’ll do this in another post). Only one of the database servers will be active at any one time. Read more »

One of the annoying “missing features” I’ve struggled with under Ubuntu is that I was unable to wakeup the PC from suspend or hibernate with my keyboard. Of course, Windows just does it – tap the keyboard and the PC starts up again. I could press the power button on the front of the PC, but its down the side of the desk and not easily accessible.

I found an older post in the Ubuntu forums that had the fix for USB devices and it also works for PS2 with the simplest of changes. So follow these steps and you should be saving power and getting back to work faster.

Open a Terminal and type,

cat /proc/acpi/wakeup

Note the entries that come back and you should see a device called “PS2K” toward the top if you have a PS2 keyboard. For those with USB, it’ll be one of the USB items toward the bottom. The entry will probably also have “Disabled” on the same line, hence your problem.

To enable this entry, switch to a root session by typing,

sudo -s

and enter your password. Now type the following to update the acpi file and toggle “disabled” to “enabled”, (those with USB devices can try USB0, USB1, etc)

echo PS2K > /proc/acpi/wakeup

That should have now enabled your PS2 keyboard to wakeup your PC for this session. Give it a test by putting your machine to sleep and then tapping a key on your keyboard. Probably a good idea to save stuff first, just in case.

If you tried changing a USB device, it may take a few guesses until you find the KB. My mouse was USB0 and clicking any mouse button can also do the wakeup task.

To make this change permanant, you need to add that line to a script and run it when Ubuntu starts. So we create a file called wakeup.sh with the following contents,

#!/bin/bash
echo PS2K > /proc/acpi/wakeup

Save it and from a Terminal make it executable so it runs properly as a script and not just a text file,

chmod +x wakeup.sh

Now to add it to the startup area go back to your Terminal that’s running as root. We need to copy the file to the correct location and add it to the startup processes. You’ll need to run the cp command in the same folder as where you saved your wakeup.sh file.

cp wakeup.sh /etc/init.d/wakeup.sh
update-rc.d wakeup.sh defaults

Now when you reboot, the script will run and enable your PS2 keyboard in ACPI so you can wakeup your PC.

Installing the free VMware Server is a common but slightly tricky process on some newer Linux systems. Having had to go through it again recently I thought I’d write some of it down. Of course if you are using Ubuntu 7.10 then the simple option is to enable the Canonical Partner repository and just use Synaptic to select and install VMware Server.

For the others in the audience that are installing on Ubuntu 8.04 or another Linux system that doesn’t have packages, you should have a working VMware Server install with web interface and a client console by the bottom of the page. Read more »