This site certainly has seen it's share of hosting environments. It started on a shared hosting, without even a proper domain name, then later moved among many of the popular virtualization techniques, first VMware server, then KVM and finally Xen (VPS). But, most of that time, it somehow wanted to end on a real hardware, to have a room to breathe, so to say. As my page on the subject of the digg effect clearly shows, there are times when load on the web server increases rapidly, and to survive such sudden rise in interest, it's best to be hosted on a proper dedicated server. Also I remember that the ever popular picture of Linus Torvalds giving thumbs up to Windows 7 OS ate a fair amount of bandwidth in short time.
The problem is, dedicated servers can get really pricey, because you're leasing not only the physical hardware, you also expect the server to be in a properly air-conditioned and secured data center, connected to UPS, have a good network connection and you also expect the hosting company to pay for all those electricity, cooling and networking bills for you. And of course to install the OS for you and to quickly replace any malfunctioning part etc... All this quickly adds up and pricing goes through the roof fast, thus making most of the real (enterprise) servers completely out of the reach from hobby projects like this site. Fortunately, in the last few years, there has been a steady growing market of so called green servers, small and affordable units that are more energy efficient, possibly more densely packed and certainly more affordable, but still giving great performance to those for whom the absolute availability is not the first priority.
GSmartControl is a graphical user interface for smartctl (from Smartmontools package), which is a tool for querying and controlling S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) data on modern hard disk drives. It allows you to inspect the drive's S.M.A.R.T. data to determine its health, as well as run various tests on it.
Alexander Shaduri has done a decent job making a very useful GUI for an otherwise fairly cryptic S.M.A.R.T. attributes. When running GSmartControl you have helpful tips, color coded lines, help built into application, you name it... Few days ago it became available in Debian sid, but you can always visit the official GSmartControl page, download and build it for yourself.
Debian's FreeRadius package is built without support for EAP/TLS/TTLS/PEAP because of the licensing problems of the OpenSSL library. But, if you want to implement 802.1x network authentication with strong security, you'll need it. This is a short tutorial that explains how to build Debian (sid aka unstable) package linked to libssl and with EAP/TLS/TTLS/PEAP support compiled in.
First, download the newest source package (orig.tar.gz), Debian diffs (diff.gz) and description file (dsc) from the freeradius package page. The version I tested the procedure with is 1.1.7-1.
You've finally made the move to a Windows-free computer, you're enjoying your brand new Linux OS, no trojans/viruses, no slowdown, everything's perfect. Suddenly, you need to update the BIOS on your motherboard to support some new piece of hardware, but typically the motherboard vendor is offering only DOS based BIOS flash utilities. You panic! Fortunately, this problem is easy to solve...
Step 1: Download FreeDOS boot disk floppy image
FreeDOS, a free DOS-compatible operating system, is up to the challenge, no need for proprietary DOS versions. So, all you need is a bootable floppy disk image with FreeDOS kernel on it. We are fortunate that guys at FDOS site have prepared one suitable for us. Use the OEM Bootdisk version, the one with just kernel and command.com, because it leaves more free space on disk for the flash utility and new BIOS image. You can also find a local copy of this image attached at the end of this article. After you download the image, you need to decompress it. In other words:
With a little bit of torturing, and some fun on the way, find out how fast your hard disk drive really is.
1-Terabyte hard disk drives are slowly coming to the market, so I suppose we can't complain that we don't have enough space to save (the ever increasing amount of) our precious data. But, it's also a known fact that although disk storage capacities are improving at an impressive rate, disk performance improvements are occurring at a rather slower rate. Unfortunately, larger disk doesn't always mean faster disk. What follows is an explanation of two techniques for measuring disk performance in Linux.
The upcoming 2.6.20 Linux kernel is bringing a nice virtualization framework for all virtualization fans out there. It's called KVM, short for Kernel-based Virtual Machine. Not only is it user-friendly, but also of high performance and very stable, even though it's not yet officialy released. This article tries to explain how it all works, in theory and practice, together with some simple benchmarks.
A little bit of theory
There are several approaches to virtualization, today. One of them is a so called paravirtualization, where the guest OS must be slightly modified in order to run virtualized. The other method is called "full virtualization", where the guest OS can run as it is, unmodified. It has been said that full virtualization trades performance for compatibility, because it's harder to accomplish good performance without guest OS assisting in the process of virtualization. On the other hand, recent processor developments tend to narrow that gap. Both Intel (VT) and AMD (AMD-V) latest processors have hardware support for virtualization, tending to make paravirtualization not necessary. This is exactly what KVM is all about, by adding virtualization capabilities to a standard Linux kernel, we can enjoy all the fine-tuning work that has gone (and is going) into the kernel, and bring that benefit into a virtualized environment.
Virtualization is a hot topic these days. With hardware getting more and more capable, by means of cheap multi-core processors and gobs of memory, we can expect virtualization to become only more important in the coming years. Virtualization promises reduced costs for IT organizations, both hard (machines, power, cooling) and soft (admin and operations personnel).