Submitted by Bernd Helmle on Tue, 25/05/2010 - 11:29
The PostgreSQL developers' community recently published the first Beta version of the new 9.0 release. Over 200 new functions and improvements feature in this new version. With this new release, PostgreSQL now amongst other features claims an inbuilt replication solution as well as the ability to access and read standby nodes, continuously being updated by Log Shipping (Hot Standby). Streaming replication allows the sending of transaction logs directly to one or more standby nodes, which considerably reduces the amount of time lost compared with the more common, file-based log shipping.
Submitted by Roland Wolters on Thu, 20/05/2010 - 11:40
Following our earlier introduction to RHCS we now present a real world example: the installation of RHCS with Debian to provide certain virtual machines as services. Our RHCS overview already explained the basics of RHCS. This time we will take two hosts with shared storage and provide KVM guests as services.
Installation of the nodes
In this setup the nodes are the machines which are running KVM. Each running KVM guest is a service managed by RHCS. While installing the KVM hosts you should make sure you comply with the following suggestions:
Submitted by Michael Banck on Wed, 05/05/2010 - 15:00
In May, Consultants from credativ GmbH will be holding a 3 day advanced system and network administration workshop at the Open Source School in Munich.
Training specifics (subject to modifications!):
Kerberos: This training covers the Kerberos authentification protocol, which can handle a range of services and operating systems transparently. The use of tickets makes single-sign-in possible; so a user can access all services with a unique log in. The training will be aimed at network and system administrators who wish to roll out Kerberos in their business or administrative network; it will also cover the installation and management of Kerberos, as well as the integration of services and client programs.
Submitted by Bernd Zeimetz on Mon, 12/04/2010 - 10:09
Lighttpd is a web server with a fast growing user base. This howto will demonstrate how redirects can be done based on the language of the user's browser. While migrating from our old blogging software to Movable Type we decided it would be a good idea to show the blog's welcome message in English or German depending on the language setting of the user's browser. Since one of the reasons for the switch to the new blog engine was that Movable Type creates static html pages, we avoided cgi scripts or similar workarounds.
Submitted by Bernd Helmle on Fri, 26/03/2010 - 13:57
The OOM-Killer can cause nasty surprises on machines with a heavy memory load; processes are cancelled or terminated without warning. Fortunately, this behaviour can be adjusted with some clever kernel tweaks. Administrators of Linux machines with a very high RAM-Usage are sometimes faced with a terrifying scenario: the Linux OOM-Killer (OOM = Out Of Memory). In situations such as a crashed PostgreSQL instance, the following entry can typically be found in the server log:
Submitted by Roland Wolters on Wed, 24/03/2010 - 15:30
This week, credativ launches its Open Source Support Card. With this card Open Source Support can be bought at a fixed price - without a binding contract. After a long preparation phase we are now offering our trusted services in a new, simple format; with the Open Source Support Card you get a fixed contingent of project-specific, pre-paid services. Customers using the Open Source Support Card have the unique advantage of full cost control; the card can be purchased as a product, without any obligation to sign an agreement for a specific length of time.
Submitted by Roland Wolters on Fri, 19/03/2010 - 13:55
Many digital cameras today do not just save an image, but also save various meta data in the Exif standard. This data includes information about the position of the camera when the image was taken (such as vertical or horizontal). However, some image programs use this data to rotate the image when displaying it while others don't, leaving the user to face inconsistent behaviour. This can be fixed with the tool exiftran; it automatically rotates all images according to the Exif data, which it discards afterwards. It is also very easy to use for mass conversion:
Submitted by Roland Wolters on Fri, 19/03/2010 - 11:20
The tool chain of a sys admin should always be comprised of effective tools. Today we are introducing the package sysstat.
Sysstat is a collection of command line tools dedicated to providing the system administrator with a quick overview of the performance of the system. They work as front-ends to the Kernel and therefore can never provide more data than the Kernel itself gathers, although the interface is much more user-friendly than querying Kernel parameters manually.
iostat is the way to go if there are problems with the throughput of a disk, NFS storages or the CPUs. For example, if your system is behaving strangely, iostat can be used to identify I/O waits:
Submitted by Roland Wolters on Mon, 15/03/2010 - 10:21
During the Games Developer Conference the Khronos Group released new versions of its widely used 2D and 3D graphics API, OpenGL. Besides the expected Version 3.3, they also released OpenGL 4.0. From 2004 - 2008 there was so little movement from OpenGL that it was practically announced dead, falling badly behind its competitor DirectX. However, since 2008 the responsible Khronos Group has regained its footing and focused on the further development of the graphics specification. In 2008 version 3.0 was released and in 2009 two more releases followed. 3.3 was on the cards for this year's Games Developer Conference, and OpenGL did not disappoint. However, the audience was caught by surprise when the immediate availability of OpenGL version 4.0 was also announced.
Submitted by Roland Wolters on Fri, 12/03/2010 - 10:00
Phoronix has used its Test Suite to compare the memory and power consumption of different desktop environments. However, the results should be handled with care. The "Power & Memory Usage" test was done to evaluate whether XFCE and LXDE consume less power and memory compared with their "big" siblings KDE and Gnome. The tests were done on a stock Ubuntu installation. At first glance the results suggest that KDE consumes much more power than the others. However, these results are misleading. For a start, measuring memory consumption is all but an easy task and requires a lot of thought.