Built using only Ubuntu, Crunchbang Linux has boiled down its distribution offering only the bare minimum needed to have a good balance between speed and functionality. Though not intended for older hardware, it is reported to work well in outdated environments where there is a premium placed on eking out as much speed as possible. Read more about it at http://crunchbanglinux.org/wiki/about and share with us any stories you might have in using it.
Archive for 2009
If you google around on the web you will find there are several tutorials on how to make your Ubuntu Linux installation run faster — especially on older hardware. These tips are very useful and range from minor tweaks to major overhauls. Being an intermediate Linux user myself, I found some of the more difficult optimizations to be overwhelming and not something I would want to try at home — changes to how Linux writes to the hard drive, for example. While researching and implementing the optimizations I felt comfortable with on my older Dell laptop and my new Asus eeePC 901, I jotted down all of my notes for future reference. Below are some tips for the intermediate user on how to optimize your laptop (or desktop) running Ubuntu Linux.
Most laptops have enough RAM installed that the swap space on the hard disk shouldn’t really be used. Yet the default setting for swappiness in Ubuntu is 60. By lowering it to 10 we can reduce the number of read/writes the the hard disk. This is especially handy for netbooks with solid state drives in them. To reduce the swappiness, follow these steps:
sudo sysctl -w vm.swappiness=10
- Add the following line to /etc/sysctl.conf
Preload is an adaptive read-ahead daemon that monitors running applications and analyzes them for commonalities. It then uses this data to predict what applications you might run and preloads them into memory. The result is faster startup times for commonly used programs. Installing preload is as easy. Just run the following line in a terminal window:
sudo apt-get install preload
The Boot-Up Manager (BUM) is a useful utility for starting and stopping boot-up scripts. Once installed it will appear in the System -> Administration menu. You can use BUM disable unnecessary boot-up scripts that may be slowing down your boot time. For example, I disabled saned, an API library for scanners, because I know I’ll never be attaching a flatbed scanner to my laptop. To install BUM:
sudo apt-get install bum
If you are using Gnome for your desktop manager there will be an option to select which applications are started when you login. Go to System -> Preferences -> Startup Applications and uncheck the programs you don’t need. For example, I disabled the Evolution Alarm Notifier because I don’t use Evolution for setting alarms. I also disabled the Remote Desktop server, UME Desktop Launcher, and UNR Launcher. Just be careful to uncheck them and not remove them. In the case that you’ve removed something critical, you’ll want to be able to get it back.
Replace Metacity with Openbox
Openbox is a minimalistic and lightweight window manager that is known to run much faster than metacity, its bulkier counterpart. And you can easily get it working while still using Gnome as your window manager / desktop environment. By running Openbox inside the Gnome environment your desktop will become cleaner and faster. To install it, follow these steps:
- Install openbox using:
sudo apt-get install openbox obconf openbox-themes
- Setup openbox as the default window manager by adding an entry in Startup Applications.
To do this, go to System -> Preferences -> Startup Applications and enter the following:
- Name: Openbox
- Command: openbox ––replace
- Choosing the Openbox theme and other configuration settings
Go to System -> Preferences -> Openbox Configuration Manager to choose a theme you like and to update other settings such as Appearance and Windows.
Note: changing the Desktops setting doesn’t effect the Gnome applet controlling the number of desktops. To change the number of desktops, you will need to revert back to Metacity and change them, then re-enable Openbox
That’s all for now
I found that making these few simple changes decreased load times on my older laptop significantly and made my newer netbook more minimal. Hopefully, these tips will help you as well.
When running PHP as a cron, the $_SERVER['HOSTNAME'] variable is not set, nor are any other variables that will identify which server your cron is running on. This can be problematic if you are running the same cron on multiple servers, such as in a load balanced environment, and you need the cron to report back or log information about the server on which it ran.
Here is some code for getting the hostname value from your linux network configuration, assuming you have setup /etc/sysconfig/network properly.
//get hostname info from /etc/sysconfig/network
preg_match('/HOSTNAME=(.*)/', file_get_contents('/etc/sysconfig/network'), $network);
$hostname = split("\=", $network);
echo $hostname; //this equals the value of your HOSTNAME
UPDATED February 19th, 2010: As BobM pointed out, the original solution to this problem didn’t account for fractional decimals. Originally I didn’t include them because Intervals didn’t require that level of precision, but apparently fractional decimals are quite common elsewhere. Because of that, I’ve updated this post, along with the regex, to include support for fractional decimals.
For the Intervals API, we’re wrestling with issues surrounding data input validation. This recently became interesting when the matter of date validation came up. Ordinarily, Intervals allows many, many different date formats, dependent on the locale that the customer is using (for example, Intervals may expect the date format ‘mm/dd/yyyy’ for US customers, ‘dd.mm.yy’ for a customer in Austria).
For our API developers, we wanted to use a common, universal format, one that would be easily compatible with our application and database layers. For that we selected ISO 8601, which is great in terms of widespread use, but not so great in terms of how complicated its specifications are.
Generally, ISO 8601 looks something like ’2009-05-20′ for dates and ’2009-05-20 12:30:30′ for date/time combinations. These two examples encompass 98% of the user input we’re likely to encounter. But we wanted to make sure that if we told developers they could use ISO 8601 dates, our system would support it. (more…)
Ubuntu Linux: How to setup a VPN connection to a SonicWall router using Openswan and Pre-shared Keys (PSK)Monday, May 18th, 2009
Pelago is a web design and development agency in Santa Barbara, California. Since our humble beginnings in August of 2000, we’ve seen the Internet landscape evolve exponentially in the last nine years. Our most current challenge as a creative and engineering agency is in embracing diversity in platforms and the inevitable shift towards the remote office. We use three different operating systems — Windows, OS X and Linux — on a daily basis. In addition to developing web-based project management software that is compatible with all three platforms, our designers and developers rely on them inside and outside of the office. Tunneling through the firewall from outside the office was our next requirement for embracing a diverse and distributed remote office.
Our SonicWall router makes it easy enough to establish a VPN connection using Windows. There is a client that can be downloaded from the SonicWall web site. What about other operating systems? Our developers often use Ubuntu Linux from home and required a way to VPN into the office. Once established, a VPN connection allows access to development servers, remote desktops, and other network resources inside the firewall; so you can see why it would be essential for the remote office.
The problem, as most Linux users out there already know, is that setting up a VPN connection in Ubuntu Linux is not very easy. After much trial and error, here is how we got the VPN working on Ubuntu Linux using Openswan.
Configuring the SonicWall Router
Login to your SonicWall router admin and make the following adjustments to the VPN settings.
Click on the VPN link and note the Unique Firewall Identifier for your SonicWall router. You will need it later for the value
- Under VPN Policies, create or edit the ‘GroupVPN’ policy.
- Click on the General tab and set the following:
- IPSec Keying Mode: IKE using Preshared Secret
- Shared Secret: shared.secret.key (enter your secret key here)
Click on the Proposals tab and set the following:
- IKE (Phase 1) Proposal
DH Group: Group 5
- Ipsec (Phase 2) Proposal
- Enable Perfect Forward Secrecy (checked)
DH Group: Group 5
- IKE (Phase 1) Proposal
If you are using Ubuntu, open a terminal window and type in:
sudo apt-get install openswan
The install will ask you a few questions about how you want to set it up. Select the suggested default for each step. This will install Openswan and create the ipsec.conf and ipsec.secrets configuration files.
Add the following connection parameters to your /etc/ipsec.conf file:
left=192.168.2.31 #your IP
right=xxx.xxx.xxx.xxx #IP address of your sonicwall router
rightsubnet=192.168.1.0/24 #gateway IP for your LAN. This will work for most
Update: After upgrading to Ubuntu 9.10 a few things changed in the conf file. First, I had to comment out ‘xauth=yes’ as it was throwing an error.
Add the following line to your /etc/ipsec.secrets file
@GroupVPN @sonicwall.unique.identifer : PSK "shared.secret.key"
Starting and stopping the VPN connection
Starting ipsec and opening the VPN connection
sudo ipsec setup ––start
sudo ipsec auto ––add sonicwall (note: if you change the configuration files, you'll need to run 'sudo ipsec auto ––replace sonicwall' to reload the file)
sudo ipsec whack ––name sonicwall ––initiate
Closing the VPN connection and stopping ipsec
sudo ipsec whack ––name sonicwall ––terminate
sudo ipsec setup ––stop
The following links were useful for getting the VPN connection up and running on Ubuntu Linux:
Openswan wiki page for SonicWall routers:
SonicWall PDF instructions for using Agressive Mode and IKE with Pre-shared Keys
We are now on our third SonicWall Router. The original 170 didn’t have enough features for us. It’s replacement, the 2040 recently went belly up. We are now running on the 2400. When we made the upgrade the Linux VPN stopped working. Checking the logs on the 2400 revealed a message stating the IDs did not match during Phase 1 IKE. It took some googling to figure out but the fix was to change the leftid so that it matched the name of the security policy. In this case, GroupVPN:
Another update you can make to the above configuration is to add the following lines to your configuration to allow VPN access from any IP:
The last two hours have seen the Jesusita fire take a turn for the worst due to hi temps, hi winds, and low humidity. Our offices are two blocks from the evactuation warning zone and most of downtown Santa Barbara is now in the evacuation warning area. Here is an updated Google map with the evacuation zone.
I’ve been following some rants on hacker news and reddit dealing with CSS vs Tables, read in this order when you get a chance:
The last article sums it all up in my opinion.