Rainbow Chard

An assortment of indigestible things

Support your local post office: don’t print your own postage!

The Royal Mail‘s Print Postage Online service can save a huge amount of time if you’re sending something that falls foul of their arcane pricing structure. You can print out a personalised label, bung it on the envelope, and—if it’ll fit in a postbox—send it on its merry way all by yourself.

I’m not actually suggesting that you avoid this service altogether: it’s just too useful, and is to stamps what the debit card has become to pocketfuls of change. Clearly its use for ordinary post is a loss to Post Office branches, but there’s a way in which it actually costs them money. If you print a label for a service that requires the item to be handed in (like special delivery, so it can be barcoded and scanned on submission), your local post office gets absolutely nothing. As they have to spend time processing the item, which can take a few minutes, and then storing it on their premises, sending items in this way is directly detrimental to that branch.

Many smaller branches’ postmasters are not salaried, and only make a living through transaction commission. Sadly and bizarrely, handing in a pre-printed item for processing is not seen as a transaction: even though the branch does most of the work, they don’t actually make the sale.

Most people, especially in rural areas, are keen to support their local post office for themselves and their community. So do them a favour: if you need their help to send stuff, let them take your money. You’ll make a postmaster very happy.

Using ‘ab’ to benchmark with different (or random) requests

If you’ve ever needed to benchmark (or load test) a webserver, you’ll be familiar with Apache Benchmark (ab), a brilliant tool that will hammer your webserver with lots of concurrent requests and give you statistics, histograms and and graphs—everything apart from how hot the server got! This is useful to determine when things like the network and webserver processes hit some limit or other, but for a modern web application it is of limited use, because more than likely you’ll end up requesting a cached page over and over again.

Motorway service areas: what are they for?

Anyone who has driven a reasonable distance in mainland Britain will have spent much of that time staring blankly at three lanes of fast traffic, speedometer pegged at 70, occasionally swearing at middle-lane hoggers, periodically being asked if we’re there yet, and wishing for it to be over soon. And if you’ve spent more than a couple of hours doing that, you’ll have given in to hunger, thirst (whether yours or the car’s) or bladder pressure and visited the most British of hell’s circles: the motorway service area.

Creationism in British schools, the Big Bang, and a small Mouse

A particularly dodgy textbook

If you live in the UK and have any interest in politics, education or science, you’ll know that a minor kerfuffle has arisen over the apparent intention of some new free schools to teach a creationist viewpoint as some level of fact. Many people sensed the dark cloud of events in the US on our horizon: dodgy textbooks, partisan school boards, and a generation of children that have been ‘taught the controversy’.  The issue has received a modicum of coverage in the quality (and not-so-quality) press, a small storm of activity on Facebook and Twitter (and maybe Google+, who knows?), and even a petition to the government with a signatory count well into five figures.

Using ZoneMinder with a cheap CCTV camera

One of the server rooms I look after has an old CCTV camera in the ceiling, and I decided to press it into service to enhance security for that room. I now get alerts from Nagios when motion is detected, so that I can go and see who’s been poking around. Here’s how I got there.

Restoring datastore performance graphs after upgrading to vCenter 5.0U1

Datastore performance data graphs just say 'No data available'


My recent upgrade from ESXi and vCenter 4.1U3 to 5.0U1 went so smoothly, I should have known that not everything was as it should have been. My battle scars from decades of fighting buggy software (in other words, software) were tingling, and it wasn’t too long before I found the problem. All my datastores’ non-realtime performance data graphs—which I rely on for troubleshooting slow VMs—were blank. ‘No data available‘ was all I got. A call to the refreshingly excellent VMware support folk resulted in a pointer to this KB article. It’s a bit involved, especially if you don’t already have PowerCLI installed, so here’s a quick walk-through.

Getting ESXi 5.0 to use a remote syslog server

I just had a quick call with a very helpful VMware support guy about this. I’ve just upgraded my ESXi boxes from 4.1 to 5.0, but I wasn’t getting any messages at my remote syslog server any more. Here’s a quick guide to making it work.

Dying of AIDS? Cheer up: you’d have died eventually anyway!

As I slowly go through all my old radio memorabilia, I’m rediscovering all sorts of interesting things that I haven’t seen for decades. They range from the mundane to the historically fascinating, but this particular example is perhaps the most unpleasant item I’ve found so far.

Metered estate lock-in: an update

This article was written in 2012.  I no longer live in the area and don’t have any more up-to-date information.  I’m leaving it here for reference only.

My previous post about supplier lock-in and metered estates generated a modicum of interest, both in the comments and in messages I’ve received directly. It seems that there is a small but significant number of medium-to-large metered estates where the consensus necessary for switching suppliers is rendered impossible by the inevitable turnover in fixed-term contracts. The Competition Commission’s order requires that all residents on a metered estate must be free of fixed-term contractual obligations before a switch can be made.

Rather than updating the original post again and again, I’ll summarise what I’ve found out so far.

Moving from Debian ‘stable’ WordPress to the latest version

I’ve been running WordPress 3.0.5 for a while now, as it’s the version in the current Debian ‘stable’ repository. For a while now I’ve been meaning to move to the latest and greatest (which, as I write, is 3.3.1), but didn’t want to mess about with pinning in apt to run a ‘mixed system‘. WordPress has had its own automatic upgrade system since 2.7, and with a history of nasty vulnerabilities, I want to be able to apply upgrades as soon as they are released by the WordPress team.

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