HowTo: Create a Diskless workstation that boots from PXE using Ubuntu
Diskless booting is where a PC starts up purely from a network connection. It does not have a physical hard-drive in it to start from in the traditional manner.
Why would you want to do this? Well, say for example you have a MythTV Frontend PC. For the most part, most Frontends are dedicated PC’s connected to a TV or projector that are not used for any other purpose, so technically there is really no need to have a hard-drive inside one as nothing new will ever be stored (all the media is streamed from the Backend server). There’s also the added bonus of less noise by not having a hard-drive installed.
Another good example of using a Diskless boot environment is for performing offline virus scans of Windows based PC’s in a safe environment that is not Windows, using tools like ClamAV. In a corporate environment, having a “normal” installation makes it easier to setup default settings that normally don’t suit booting up from an Ubuntu Live CD, such as corporate Proxy settings. Making a Diskless Boot setup is far easier than creating a customised Live CD in this instance.
So how exactly do you create a diskless booting PC?
HowTo: Monitor the progress of dd.
The dd command is a tool used to pipe data in from a source to a destination. It has a multitude of uses ranging from creating large dummy files of a specific size to duplicating hard-drives sector by sector to another disk or to a backup file. It’s also useful for fixing problems with hard-drives that Windows refuses to deal with.
But we’re not looking at the virtues of dd here. We’re looking at its annoyances and dd has one particularly glaring annoyance – a lack of display of progress. You could tell dd to start imaging your multi-terabyte hard-drive and not have any indication of how far it has gone – you just have to wait until it finishes. The dd command only outputs some information right at the very end of its job, which could well be several hours later. The only indicator that you have that something is happening is your hard-drive light madly flashing away.
Luckily while dd doesn’t show progress during its tasks, it can be prodded externally to give up information about itself as it runs, and we can achieve that by using the kill command without actually killing the dd command’s execution.
HowTo: Get an Ubuntu Live CD to boot off a PXE server
Following my article about creating your own PXE network boot server, here is the first practical use you can put it to – taking the Ubuntu Live CD and turning it into a network-bootable version!
Network booting the Live CD has obvious advantages – aside from booting faster than CD (especially on a gigabit network), it is indispensable as an emergency boot medium in a workplace environment, especially for broken Windows systems, and allows for Ubuntu effortless installations on netbook PC’s that don’t have optical drives and saves you having to have a USB stick handy.
HowTo: Setup your own PXE Boot Server using Ubuntu Server
The Preboot eXecution Environment (PXE) provides a means of starting up a PC using a network adapter instead of the traditional method of hard-drive, USB flash stick, CD or floppy disk.
Why would you want to boot a PC from the network? Well, it opens the door to booting diskless workstations, eg: Internet Cafe PC’s, or if you regularly install tens or hundreds of PC’s, you can start the installer on all those machines at once without needing to have individual boot/install media for each machine. You can even use Linux PXE for starting Microsoft Windows network installers and tools.
This article is going to show you how to setup a standard Ubuntu 10.04 Lucid Lynx Server to respond to a PXE boot request and present a boot menu ONLY. I will put practical applications such as installing Ubuntu over the network or booting a Live CD over the network into separate future articles.
Mini-Review: Generic hot-swap eSATA Docking Bay with Ubuntu
I regularly deal with external hard-drives, be it for data backup or if I’m rescuing a client’s hard-drive from uncertain death.
Since the idea of opening my PC on a regular basis to connect a drive is a bit of a turn off, I used to use an external USB drive enclosure. This works fine, but it’s a bit slow (well, at least until USB 3.0 makes its debut). The eSATA standard allows you to connect external drives at full SATA speed, but it’s not cost-effective to buy an enclosure for every external drive you have.
Enter the Docking Bay. This is a simple weighed base that allows you to connect a hard-drive in a similar way to how you used to plug in game cartridges into a classic game console like the Atari 2600. You can then eject the hard-drive and plug another one in, all without restarting the PC.
This is a review of one such Docking Bay and how it works with Ubuntu, including the wonders of hot-swapping.
HowTo: Quickly transfer files from an Ubuntu box to another PC over a network without installing Samba, SSH or FTP.
Let’s say you have an Ubuntu PC and a second Windows PC or Mac. You need to do a quick transfer of a file or two from the Ubuntu box, but you really don’t want to go through the hassle of installing and configuring Samba or FTP just for the sake of transferring a couple of files.
Of course you could use a USB flash drive, but it takes twice as long to copy a file that way because you have to copy it to the flash drive and then copy it again from the flash drive to the destination PC. Besides that, what if you don’t have a flash drive big enough to transfer the files you want? Is there a quick and dirty way to transfer some files over a network without the need to install additional software to bridge the compatibility divide?
Indeed there is…
HowTo: Migrate an Apt-Mirror-generated Ubuntu archive to another mirror source or merge a foreign Apt-Mirror archive into yours
So, you’ve gone and created your very own local Ubuntu mirror using Apt-Mirror, and you’ve come across a situation similar to:
- You’ve decided to change where you update your Apt-Mirror archive from (eg: you’ve changed ISP’s or feel that another source is more reliable than your current one to update from)
- You’re adding another large repository to your Apt-Mirror archive (such as the next version of Ubuntu) and don’t have the quota to download it, so you’re getting a friend to download it for you from their free server using Apt-Mirror (eg: iiNet and Internode customers can access their respective Ubuntu mirrors for free), so you need to be able to merge it with your own Apt-Mirror archive and have it update from your preferred source afterwards.
So how do you do this? Read on.
HowTo: Pair your Bluetooth mobile phone with Ubuntu Jaunty for file transfers etc.
Following up my previous article of how to pair your Bluetooth mobile phone with Ubuntu Intrepid, I present this updated article for pairing your mobile phone using the updated version of the Bluez Bluetooth stack and the newer and better Blueman applet for Jaunty which greatly simplifies the process of pairing Bluetooth devices and transferring files to your mobile phone.
HowTo: Reclaim reserved disk space on non-system drives taken by the Ext3 filesystem.
I made a rather alarming discovery today, quite by accident.
Like most people, I use an external hard-drive to backup data to, or to shift things around if I’m low on space on my PC’s internal drive. Well, today that external drive reported that it was full. Damn.
So I fire up Ubuntu’s Disk Usage Analyser, aka Boabab, to find out what’s consuming the most space. I use a 1TB external drive and it’s formatted total is about 916GB, which is about right, however Boabab reported that the total consumption of data on the drive only added up to about 860GB – wtf? Even Nautilus’s Volume Properties window was reporting that the drive still had 50GB-odd free, so why is the system telling me it’s full?
I use Ext3 on my drives and, being a journalled filesystem, some space on the drive is reserved to record these journals among other functions which is expected, but 50GB worth? I did some research and found out that the Ext3 filesystem reserves 5% of disk space by default for itself! In this day and age of large drives, that’s a huge chunk of lost space!!
Thankfully there is a way to tell Linux not to reserve so much space. Read on…
Mini-Review: Transcend JF V60 32GB USB Flash Drive on Ubuntu
It was only just 10 years ago that some of the first USB Flash Drive storage solutions became available in the form of highly expensive sticks that only had a capacity of upwards to 32MB (yes, Megabytes) and had transfer speeds that were slower than molasses on sandpaper.
Today, we now have 32GB USB Flash Drives that go for a paltry AUD$95, and this is a review of Transcend’s offering.
