We've been doing a lot of load testing recently and are planning on doing a lot more, so we've developed a simple little script to make the collection of the vmstat (performance statistics) a bit quicker.

multivmstat is a php command line script which makes it easy to collect the statistics. Download the script

To run it you specify a list of servers to check:

This will run vmstat on each of the servers with a 5 second interval between samples.

It will create the following files:

Note: You mush have ssh access to each machine - ideally with a certificate so that no interactive authentication is required.

Download the script

One of the nice things about Ubuntu is how easy it makes it to upgrade between versions - typically start up update-manager and it will prompt you if there is a new version available and handle all the details of the upgrade for you. I've done numerous upgrades this way and never had any issues.

However, I have a number of ubuntu servers which I manage and previously I have upgraded them by changing the /etc/apt/sources.list and then running "sudo apt-get dist-upgrade"

Today I discovered that there is an automated script to handle it - which I presume is what powers the gui version behind the scenes.

You need to make sure you have update-manager-core installed:

Then you simply run do-release-upgrade

I've just upgraded two different servers from Feisty as it has recently stopped being supported. I upgraded them to Gutsy and then to Hardy which is a Long Term Supported version. The whole process took about an hour of which it took about 5 minutes of my attention to answer a few simple questions.

Who said Linux is hard :-) Cheers, Mark

I just reinstalled my system with the latest Ubuntu 8.10 x64 and one of the apps I use regularly for testing and developing Asterisk applications is Twinkle, which is a great VOIP softphone.

It works great, but when I tried it in my new install the sound was all choppy, i.e. I would get every half of each second of the audio.

A bit of fiddling about with the settings and I got it solved. Posting it here so when I forget about it and run into the same problem again I'll know how to fix it.

The solutions is as simple as:

• From the menu select Edit -> System Settings.
• Select Audio on the left
• Change the audio devices to use the most approriate device that is NOT "ALSA: default: Default Device" - in my case it was "ALSA: plughw:0,0: HDA Intel (AD193x Analog)"

I do like the very friendly naming scheme for devices :-) Hope it helps, Mark

MySQL has some really useful functions that make timezone support a bit easier as described in a previous blog post..

However, you need to do a tiny bit of setup work before you can use the functions. You need to load the timezone info from your system into the mysql db.

Thankfully, the MySQL Developers have included a very handy script that will do just that from a zoneinfo files which are used on Linux and on Mac's.

Obviously change the mysql params or add a -p if you have a password or are connecting to a remote server.

Check out the MySQL developer site for full details on MySQL timezone support

Cheers, Mark

It should be simple to do this and it is. The hardest part was finding the correct way to do it, so for future reference:

Using the command line, you can use dpkg-reconfigure tzdata.

Follow the instructions to reconfigure the timezone. This was taken from the ubuntu wiki article

Cheers, Mark

There are a number of steps needed to get custom language files working in a nice fashion for asterisk on ubuntu.

For this example I'm going to replace the standard digits of 0 to 10 with files that I've had recorded.

Create files in the correct format:

Starting with files in the format: 0.wav, 1.wav .... 10.wav which are 44.1kHz 16 bit PCM mono wav files.

We can convert them to alaw, ulaw and gsm formats which reduces asterisk transcoding with the following script: (requires sox to be installed)

Move the files to the correct place on the server:

I'm going to use the name 'learnosity' for the language as these are the files that we've recorded. So we need to create the following directory on the asterisk machine:

If you wanted to do more audio files, you can create learnosity directories for the other audio files.

Once this is done, copy the alaw, ulaw and gsm files in but leave the original wav files out.

Tell asterisk to use these files:

The easiest way to use these language files is to set the channel language for the sections you want to use it:

Here's an example from extensions.conf:

If you dial extension 4 you get the digits 1 to 9 in the default language and if you've done everything correctly you will get your newly recorded digits the second time.

Cheers, Mark

I was recently setting up a Ubuntu server and was partitioning it after it had been installed.

There was lots of free space on the drives as the root partition was only using a small portion of the disk. After running fdisk to partition it and mkfs.ext3 on the partitions to format them I couldn't see them in /dev/disk/by-uuid.

A quick google presented the solution:

According to the man page this makes udev request the kernel device uevents, which in essence makes it read the disk info again and show it all up so you can mount it happily.

Cheers, Mark

I've been working on getting CF Sandbox security working. It's trickier than I first thought so here's how to do it for future reference:

Enable security Manager

Instructions from Steven Erat's blog:

NOTE the example from the adobe site has the quotes in the wrong place. Note you also need to change [cf_webapp_root] to match the location on your machine.

Datasources

After I enabled Datasource security I began to receive the following error, a bit of digging reminded me that the MySQL connector tries to do some autoconfiguration for coldfusion to optimise it.

It was failing to load the configuration file which is inside the mysql connector jar file /com/mysql/jdbc/configs/coldFusion.properties

I haven't gotten to the bottom of why it couldn't be loaded but adding the following to the datasource query string fixed it up:

I would suggest adding some of the settings from this file as paramaters in your datasource settings as per previous post

Note: This was using the following:

• ColdFusion 7.0.2 Cumulative Hotfix 1 Multiserver install
• MySQL connector/J 5.0.8

Hope it helps. Cheers, Mark

A current project that we are working on requires us to be able to record sound via a flash plugin. Initially I thought it would be nice and easy as I've seen demos of both video and audio broadcasting - however, the one big problem is that the current flash client only allows you to record video to a netstream, you can't get any access to it in the flash player.

So you need something like Flash Media Server or Red5 to record it.

However, once you record it to the server it is an flv and the audio codec is stored as a NellyMoser encoded audio portion. This codec is not supported by many applications and after a quick google found the nelly2pcm project on google code.

This will convert a flv sound file to a raw pcm file - which you can then do useful stuff with. So here's how to do it on a Ubuntu machine.

• Ensure you have build tools: (apt-get install build-essential)
• Download nelly2pcm from google code
• Extract and Compile it,

You should now have a nelly2pcm executable file in this directory.

You can run it as follows:

This will create a raw sound file with no headers and output the line above which you'll need for the next part.

To play this file back you can use sox (apt-get install sox)

If you've got all the options correct then this will play the file back. Once you got it correct you can then use sox to create a wav file which is essentially the same except that it has a header which contains all the settings (eg bitrate etc)

From a wav you can convert to whatever you like. I'm looking forward to the Flash Player 10 release as this messing will no longer be necessary as it will support encoding with the free Speex codec.

Cheers, Mark

Update:

In the 12 hours since I wrote this post it appears that a DMCA takedown notice has been served on the nelly2pcm site and google have taken it down. I've no idea if it's related to this post or not and no details are available yet on the chillingeffects site but hopefully it will be updated shortly. As I mentioned earlier, I can't wait for flash 10 with the speex codec so we don't have to use Nellymoser, well done Adobe for including it.

I was cleaning up some source code yesterday and wanted to print it all out, however the Mac line endings (we use Mac's and Ubuntu mostly) were messing up the printout on my Ubuntu machine.

A quick google later and I found the solution, a program called 'tr', posting here for next time:

Obviously you could convert from Unix to Mac by reversing it.

Cheers, Mark