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.
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: 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: The Fujitsu Dynadisq III 320GB USB Portable External HDD
Actually, I tell a lie – the full title for this product is the “Dynadisq III High Speed USB 2.0 Portable Storage & Backup Solution for Fujitsu 2.5″ SATA Disk Drives” (say that in one breath 5 times)!
Title aside, this is one of yet another series of pre-packaged drive & enclosure solutions being bandied about the market today. These solutions are gaining interest with a lot of consumers because they generally manage to undercut the combined cost of buying the same hard-drive and enclosure separately, so much in fact that many users who only need the drive, buy the solution package, rip out the drive and discard the case because in some cases (pun not intended), it can be cheaper this way.
Cost aside, what if you simply need to have a cost-effective external portable backup solution with minimal hassles? That immediately calls for a notebook hard-drive that can be powered by the USB data cable.
