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Author: halfgaar

Halfgaar is Wiebe. Wiebe is a contributing author on this weblog. He also has a lot of stuff (such as long, in-depth articles) on his personal website.

Wiebe works at YTEC, where he is a senior developer of customer-specific tailor-made software (“klantspecifieke maatwerk software“) for clients in a few select markets: wholesale, printing and healthcare.

Kart racing scores

I want to keep track of my kart racing scores: dateTrackRacerfastest Time 2012-07-24Long BeachWiebe55.95 2012-07-24Long BeachWiebe56.22 2012-07-24Long BeachWiebe58.84 Read More »

Apache mod_proxy configuration for The Pirate Bay

I found several apache mod_proxy configs for setting up a proxy for The Pirate Bay, but none worked fully. Read More »

Listing MySQL table sizes

This query lists the sizes of all tables in MySQL: SELECT TABLE_SCHEMA, TABLE_NAME, CONCAT(ROUND(data_length / ( 1024 * 1024 ), 2), 'MB') DATA, CONCAT(ROUND(data_free / ( 1024 * 1024 ), 2), 'MB') FREE from information_schema.TABLES where TABLE_SCHEMA NOT IN ('information_schema','mysql', 'performance_schema'); Read More »

Generating an SSL CSR and key

To generate an SSL certificate signing request (CSR) with key you can do this: openssl req -nodes -newkey rsa:2048 -keyout bla.key -out bla.csr Read More »

Creating a drbd for an existing Xen domain

I needed some VMs to be available on a backup node, which I accomplished with the distributed remote block device, or DRBD. My host machine is Debian 6. Read More »

What all programmers must know about character encoding

click. Read More »

Fixing mailscanner insecure dependancy

Mailscanner cut out on me, without errors in the log. It was only after turning on debug (which prevents backgrounding and it then only processes one batch) that it showed me. Read More »

Setting max memory of a Xen Dom0

I've had some issues with Xen crashing when I wanted to create a DomU for which the Dom0 had to shrink (see bug report). Therefore, it's better to force a memory limit on the dom0. That is done with a kernel param. Read More »

Fixing a broken Xen DomU after upgrading to Ubuntu 11.4 (Natty)

My Xen DomU's that I upgraded to 11.4 no longer booted, because the xen-blkfront module is missing from the initramfs. To fix, do this when you get the initramfs prompt: Read More »

Fixing a Xen DomU’s grub config

When you use xen-create-image to bootstrap an ubuntu, it sets up a grub config file menu.lst. However, this boot config is not kept up-to-date with newer ubuntu's because they use grub2 (which uses grub.cfg and not menu.lst). And Xen's pygrub first looks at menu.lst, so if you have a stale file, it will always boot an old kernel. Read More »