All Posts By

Barney Desmond

IPv6 NAT from a webhosting perspective

By | Technical | No Comments

IPv6 is something that’s been coming for a long time now, to address the shortage of IPv4 addresses. If you’re not familiar with the problem, it goes like this: Networked devices need addresses to find and talk to each other. When the internet was invented there was capacity to address up to 4 billion devices. We’re now running out of addresses for all the networked devices in the world. There are two established technological ways out of this problem: Be frugal and share addresses, this is called NAT Move to a system with capacity for many more addresses, this new system is called IPv6. It’s not compatible with the old IPv4 system, but it gives us about 50 octillion addresses for every person on the planet NAT is a really…

Read More

Brace yourselves, Devops Downunder is coming

By | Company News | No Comments

Devops Downunder is just two weeks away now, and Anchor is excited to be a gold sponsor. In addition to being a sponsor, our very own Geek Supreme Matt Palmer will be speaking. If you’re a regular reader you’ll know that we love us some APIs, and Matt will be talking all about building a service-oriented architecture from them. Devops is about bringing together the best parts of software development and professional operations. We can guarantee that there’ll be smart minds in abundance at Devops Downunder, so whichever side of the fence you’re from there are shoulders worth rubbing. Still not convinced? Anchorites will be in attendance, and you know we’re good for a yarn over some refreshments. 😀 Devops Downunder is on the week after next, Friday and Saturday…

Read More

Use mscgen for kickass diagrams in your documentation

By | Technical | No Comments

One of the traits of a great sysadmin is writing good documentation. Good documentation means all the important stuff isn’t locked away inside your head, which is a Very Good Thing. Some might say that keeping it to yourself is great for job security, but it’s pretty short-sighted. Writing it down means you can: Delegate tasks to your very own PFY Ask for a holiday every now and then Avoid being hassled while sunning yourself on Kuta Beach because you’re the only one that knows how to fix RunsYourEntireBusiness ’99 when it explodes On the downside, you open yourself to: A smooth transition when you leave for greener pastures, and your replacement has an easy time settling in and picking up where you left off We think diagrams are an…

Read More

How hard is it to set the service tag on a Dell motherboard?

By | Technical | 4 Comments

Dell is a weird, weird place. A little while ago we had a server with a bad motherboard, one of the 5-volt lines was out of whack. No big deal, we’d just get a replacement part and swap it out (getting a Dell technician into Globalswitch datacentre is more hassle than it’s worth). Our datacentre monkeytechnician replaced the motherboard without incident, but they did notice that there was now no service tag attached to the motherboard. This isn’t a problem, but it means the DRAC card can’t report its identity properly. We asked Dell for advice on writing the service tag to the new hardware, and they promised to send through details. That evening we received two emails from two different Dell support staff, each with very different instructions on…

Read More

A dev’s guide to safely escaping and encoding URLs

By | Technical | One Comment

A lot of the support work that we do here at Anchor involves looking at websites. You could say that we’ve seen a few websites in our time. Something we come across pretty frequently is inadequate protection when it comes to handling user-submitted form data and URLs. This might not seem like a big deal, but it has some pretty big security implications, mostly relating to cross-site scripting. These problems can enable malicious activity like leaking of private data. The short version is that user-supplied data can never be trusted, and you need to carefully escape and format the data to make it safe for the intended use, such as printing it on a webpage. A very simple example Let’s say you run a site that accepts news tips from…

Read More

Making the web faster with SPDY

By | Technical | No Comments

The past year has seen substantial adoption on the web of a new protocol called SPDY (pronounced “speedy”), mostly being pushed by Google. If you haven’t heard of it, SPDY aims to improve the use of HTTP, the usual protocol for delivering web pages from servers to browsers. SPDY is exciting because it should make the web feel faster on modern high-speed connections, and improve security by making encryption ubiquitous. Up until fairly recently, SPDY remained something of a technical curiosity as it wasn’t widely supported. Both the server and the browser need to talk SPDY for it to work, which meant the benefits were mostly restricted to using Google Chrome with Google’s own services. That’s turned around in the last 12 months as several high profile sites are now…

Read More

How big is the meteorite?

By | Technical | No Comments

Hardware failure is a fact of life when it comes to computers, which is at odds with trying to keep a service running 24/7. No one can guarantee absolute perfect uptime, but it’s possible to get pretty darned close. If you design things solidly and are willing to throw money at the problem, you can make fantastically reliable systems that suffer very little downtime due to hardware failures. Engineers talk about this in terms of “nines” – two nines is 99% uptime, four nines is 99.99% uptime, and so on for any other number of nines. Anchor, for example, regularly achieves better than three nines (99.9%) per month, approaching four nines. This sort of reliability doesn’t come cheap. For each extra nine that you add, you’re reducing the downtime by…

Read More

How to smack people in the face with your resume

By | Technical | No Comments

It’s hiring time again here at Anchor1 and that means we’ve been sifting resumes. Lots of them. We’d like to offer some advice. There’s no shortage of advice on what to put in a resume, how to format it, and how to highlight the most salient terms. All that still applies, but our advice is not about that. You don’t have much time to make an impression with your resume. Let’s make the seconds count by cutting the cruft from your resume and focusing on what matters. Short is good, shorter is better. We think this also applies to resumes: Keep your resume to 1 page. But, you might say, my career history is far too extensive to keep to a single page. That’s a nice problem to have, but…

Read More

Second strike with Lightning!

By | Technical | 2 Comments

We put Kyoto Cabinet under the gun recently as a means to improve Redis. The Anchor Propulsion/Internet Laboratory validated Kyoto Cabinet as “fresh”, but extended live testing has revealed sub-optimal behaviour in some situations. To recap, we used Kyoto Cabinet to give Redis near-realtime disk persistence with a greatly reduced memory footprint; we called this “NDS” and published the code. Dirty keys are flushed from memory periodically into Kyoto Cabinet’s backing store. This works fantastically most of the time, but we’ve discovered that some operations cause a massive blowout in the on-disk files. Kyoto Cabinet is a key-value store. When you update a value in Kyoto Cabinet it can be rewritten in-place, unless the new value is longer than the old one. In this case, Kyoto Cabinet makes a new…

Read More

Hiring only the best

By | Technical | No Comments

Regular readers of this blog will know that we’re hiring – we’re always hiring, in fact, and we’re going to be talking about it more in the near future. Hiring good people is really hard, so a smart company is always ready to scoop up a great candidate when they crop up. Hiring is hard because there’s a lot of really good people out there, but not that many great people out there. The esteemed Joel Spolsky covered this at length over a decade ago in The Guerrilla Guide to Interviewing, but it comes down to this: We only want the very best and can’t afford to do otherwise. Here’s why… As a webhosting company, Anchor operates in a pretty unique space. We provide a level of support that goes…

Read More