Category: sysadmin

Various databases and how they scale

By chance I stumbled upon an article about databases and how they scale. It’s a great read and does an excellent job describing the various stengths and weaknesses regarding different kinds of scaling for databases. Especially the images really capture the essence. 

Test a pull / merge request before accepting on Bitbucket

Git is a great tool, but its documentation leaves much to be desired at times. Bitbucket’s documentation doesn’t fare much better. Commands mentioned in its wiki often don’t work as advertised. The fact that git’s commands are often incredibly counter-intuitive, incomplete and at times simply wrong doesn’t help either. So while you can get far […]

my_indexr: Script to drop and recreate MySQL indexes

As can be read in this article, I was in need of a method to quickly drop all indexes (except primary keys) from a MySQL database. After googling around a bit and being astonished that apparently no-one had written such a thing yet, I wrote the script that can be seen in that article. Unfortunately, […]

Increasing performance of bulk updates of large tables in MySQL

I recently had to perform some bulk updates on semi-large tables (3 to 7 million rows) in MySQL. I ran into various problems that negatively affected the performance on these updates. In this blog post I will outline the problems I ran into and how I solved them. Eventually I managed to increase the performance […]

HP Lights-Out 100i (LO100i) “Invalid username / password” when trying to connect to KVM

If you’re trying to connect to the Virtual KVM (console) on a HP Lights-Out 100i (LO100i) using the Remote Console Client Java applet, you might be getting an error in the order of Username / Password invalid Or: com.serverengines.r.rdr.EndOfStream: EndOfStream This is a known problem with firmware version 4.24 (or Earlier): The Virtual Keyboard/Video/Mouse (KVM […]

Getting started with Juju: “no public ssh keys found” error.

I’m trying out Juju with the ‘local’ environment, and ran into the following error: $ sudo juju bootstrap error: error parsing environment “local”: no public ssh keys found The Getting Started Guide mentions nothing of this error, and I couldn’t find a solution on the web. After a bit of reading, it seems Juju requires […]

Quick-n-dirty HAR (HTTP Archive) viewer

HAR, HTTP Archive, is a JSON-encoded dump of a list of requests and their associated headers, bodies, etc. Here’s a partial example containing a single request: { “startedDateTime”: “2013-09-16T18:02:04.741Z”, “time”: 51, “request”: { “method”: “GET”, “url”: “http://electricmonk.nl/”, “httpVersion”: “HTTP/1.1”, “headers”: [], “queryString”: [], “cookies”: [], “headersSize”: 38, “bodySize”: 0 }, “response”: { “status”: 301, “statusText”: […]

16 things you should absolutely configure on any new server

It seems even professional sysadmins occasionally forgets the bare minimum configuration that should be done on a new machine. As a developer and part-time system administrator, I can’t count the number of times I’ve had to waste significantly more time Here’s a, by no means exhaustive, list of things you should configure on any new […]

bbcloner: create mirrors of your public and private Bitbucket Git repositories

  I wrote a small tool that assists in creating mirrors of your public and private Bitbucket Git repositories and wikis. It also synchronizes already existing mirrors. Initial mirror setup requires that you manually enter your username/password. Subsequent synchronization of mirrors is done using Deployment Keys. You can download a tar.gz, a Debian/Ubuntu package or clone […]

Quick Introduction to LDAP Basics

Every now and then I have to work on something that involves LDAP, and every time I seem to have completely forgotten how it works. So I’m putting this here for future me: a quick introduction to LDAP basics. Remember, future me (and anyone else reading this), at the time of writing you are by […]

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