|
||||||
|
8 years ago I wrote a script to summarise Xen CPU use per domain [1]. Since then changes to Xen required changes to the script. I have new versions for Debian/Wheezy (Xen 4.1) and Debian/Jessie (Xen 4.4). Here’s a new script for Debian/Wheezy: #!/usr/bin/perl use strict; open(LIST, "xm list --long|") or die "Can't get list"; […] I’ve recently been setting up more monitoring etc to increase the reliability of servers I run. One ongoing issue with computer reliability is any case where a person enters the same data in multiple locations, often people make mistakes and enter slightly different data which can give bad results. For DNS you need to have […] Systemd has a new way of specifying names for Ethernet interfaces as documented in systemd.link(5). The Debian package should keep working with the old 70-persistent-net.rules file, but I had a problem with this that forced me to learn about systemd.link(5). Below is a little shell script I wrote to convert a basic 70-persistent-net.rules (that only […] At LCA I attended a talk about Unikernels. Here are the reasons why I think that they are a bad idea: Single Address Space According to the Unikernel Wikipedia page [1] a significant criteria for a Unikernel system is that it has a single address space. This gives performance benefits as there is no need […] Compatibility/interoperability is a good thing. It’s generally good for systems on the Internet to be capable of communicating with as many systems as possible. Unfortunately it’s not always possible as new features sometimes break compatibility with older systems. Sometimes you have systems that are simply broken, for example all the systems with firewalls that block […] Lets Encrypt is a new service to provide free SSL keys [1]. I’ve just set it up on a few servers that I run. Issues The first thing to note is that the client is designed to manage your keys and treat all keys on a server equally with a single certificate. It shouldn’t be […] Here are some basic things to do when debugging storage performance problems on Linux. It’s deliberately not an advanced guide, I might write about more advanced things in a later post. Disk Errors When a hard drive is failing it often has to read sectors several times to get the right data, this can dramatically […] The above sign was at the Melbourne Docks in December 2014 when I was returning from a cruise. I have no idea why there are 3 men and 1 woman on the sign (and a dock worker was also surprised when I explained why I was photographing it). I wonder whether a sign that […] On Sunday night I started the process of upgrading the LUV server to Debian/Jessie from Debian/Wheezy. My initial plan was to just upgrade Apache first but dependencies required upgrading systemd too. One problem I’ve encountered in the past is that the Wheezy version of systemd will often hang on an upgrade to a newer version. […] Today I ran a hands-on training session on configuring a MTA with Postfix and Dovecot for LUV. I gave each student a virtual machine running Debian/Jessie with full Internet access and instructions on how to configure it as a basic mail server. Here is a slightly modified set of instructions that anyone can do on […] |
||||||
