May 2012

Monthly Archives

ServerUsage – Measuring users’ activity on Linux hosts

ServerUsage is a Free Open Source Software system to collect and process usage statistic information from multiple computers running a GNU-Linux Operating System.

Since CatN is a “cluster” hosting company, one of the challenges is to track and analyse the customers’ activity spread on multiple physical hosts for both monitoring and billing purposes. From each physical host we need to collect at regular intervals the total disk I/O, the network traffic and the CPU ticks used by each system user, process and IP address. This “raw” log data must be then aggregated and processed on a central point to extract relevant information.

After spending some time searching for a ready-made solution I decided to start the ServerUsage project to best-fit our needs. This project is now available as a Free Open Source Software, so anyone can freely use and contribute to it.

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How to create ServerUsage RPM packages for Enterprise Linux

This is a short hands-on tutorial on creating ServerUsage RPM packages for Enterprise Linux, including, but not limited to, Red Hat Enterprise Linux (RHEL), CentOS and Scientific Linux (SL).

ServerUsage is a Free Open Source Software system to collect and process usage statistic information from multiple computers running a GNU-Linux Operating System. For more information please read the blog post: ServerUsage – Measuring users’ activity on Linux hosts.

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How to create SystemTap 7 RPM packages for Enterprise Linux

This is a short hands-on tutorial on creating SystemTap 7 RPM packages for Enterprise Linux, including, but not limited to, Red Hat Enterprise Linux (RHEL), CentOS and Scientific Linux (SL).

SystemTap provides free software (GPL) infrastructure to simplify the gathering of information about the running Linux system. This assists diagnosis of a performance or functional problem. SystemTap eliminates the need for the developer to go through the tedious and disruptive instrument, recompile, install, and reboot sequence that may be otherwise required to collect data. SystemTap provides a simple command line interface and scripting language for writing instrumentation for a live running kernel plus user-space applications.” — source http://sourceware.org/systemtap/.

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How to create SQLite 3 RPM packages for Enterprise Linux

This is a short hands-on tutorial on creating SQLite 3 RPM packages for Enterprise Linux, including, but not limited to, Red Hat Enterprise Linux (RHEL), CentOS and Scientific Linux (SL).

SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. SQLite is the most widely deployed SQL database engine in the world. The source code for SQLite is in the public domain.” — source http://www.sqlite.org.

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How to set up a build environment for RPM packages on Enterprise Linux

This is a short hands-on tutorial on creating the development environment to build RPM packages for Enterprise Linux, including, but not limited to, Red Hat Enterprise Linux (RHEL), CentOS and Scientific Linux (SL).

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NetsGraph – Statistical graphics for network data transfer

NetsGraph (https://github.com/fubralimited/NetsGraph) is a simple Free Open Source PHP class to generate statistical graphics from network data transfer.

While several free tools are available to create graphs from network data, after some quick research I couldn’t find a good fit for our needs here at CatN. So I decided to create a new tool that we can use for Customer reports, statistical analysis and billing purposes – that tool is NetsGraph.

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vCluster package structure for version 2

With the launch of CatN vCluster version 2 nearing, I will be following on from the previous posts introducing the new version and the vCluster timeline to explain one of the major changes we will be introducing. Previously we offered packages with a tiered pricing model, allowing you to select one of three pre-defined vClusters. After previewing an early alpha version at WordCamp last year as well as the feedback received from users of old version, we have dropped this rigid pricing structure in favour of a more flexible and customisable option.

When you purchase a vCluster in version 2, you will be faced with a single vCluster package option with a base subscription price of £5.00 per month. The package itself contains two products, one vCluster and a Shared Database, which are managed independently within the Control Panel and have their own add-ons and overage costs applied despite being part of the same package.

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Openindiana vs Nexentastor vs FreeNAS

In my previous post I gave a (very) high level overview of ZFS and why I think it is a solid foundation for vCluster. What I did not say though, was why we chose OpenIndiana over the other operating systems offering ZFS.

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Just before Sun was bought by Oracle, Solaris came in 2 flavours. Solaris and Opensolaris. As the name suggests, OpenSolaris was open source and Solaris was the closed source variant. OpenSolaris was to become proper Solaris some day and development was to be made in the open. Because OpenSolaris was opensource, many different projects were born out of it. Nexetnta made a storage appliance. Belenix was a generic desktop with KDE. StormOS was a simple desktop with Xfce. FreeBSD which had lost it’s edge to Linux over the years, took the chance and ported ZFS with great success. Joyent based their cloud 100% on Opensolaris. They even offer their version, called SmartOS, free to download and use in production.
Alas, Sun was bought by Oracle, Oracle closed the Solaris source code and open development of OpenSolaris ended.

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An introduction to ZFS

One major part of the new vCluster release is storage. As you may know, vCluster uses NFS extensively, so we want to make sure that it works reliably. Reliability means that the data stored is always available, meaning that the server should be able to handle the load and be stable, but also that the data is written correctly and consistently on disk. We also need some kind of replication for backups and maybe fail over.

There are lots of systems we could use to serve NFS. There is Linux of course, FreeBSD, OpenIndiana and a slew of commercial solutions from companies like EMC, NetAPP, HP, Dell etc. Looking around and testing various solutions we decided that Openindiana is the best solution for our needs. The main reason is ZFS.

Some background

ZFS is a filesystem originally developed by Sun Microsystems. It was released in late 2005 in the development builds of Solaris. When it was released it obliterated anything freely available at the time. It had features that where not even in the radar of other filesystems. Read More

Fake Corsair USB sticks

Some days ago we ordered some 8GB USB sticks for our custom made storage systems (I’ll write several blog posts about this later). The sticks were Corsair Flash Voyager 8GB. I personally have one, albeit 4GB, and I have been using these for years now with great success.

When the sticks arrived, I opened one of them and I noticed something strange. The stick was smaller, lighter, the logo was a bit off and the colour of the stick was different.

Spot the fake:

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