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Technical

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…

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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…

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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…

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Making the web faster with SPDY

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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…

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How big is the meteorite?

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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…

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How to smack people in the face with your resume

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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…

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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…

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Let us take your breath away with Wheezy!

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A new version of the Debian GNU/Linux operating system, version 7.0 (codename “Wheezy”) has been released today. Thanks to the open and transparent development cycle of Debian, we have been able to work on improving our support for this release ahead of time, and are happy to announce that we now offer our market-leading Anchor Complete support on Debian Wheezy immediately. Aside from the improvements and new software versions shipped with Debian Wheezy, we are also supporting some newer versions of software we like that didn’t make it into the release. When you choose Anchor Complete support with Debian Wheezy, you also get full support for the following: nginx 1.4 with SPDY built in Percona 5.5 (performance-enhanced MySQL fork) PostgreSQL 9.2 with massive performance gains Redis 2.6 with NDS If…

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Hiring only the best

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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…

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Meet Michael, (another) Linux nut!

By | Company News, Technical | No Comments

Michael Sampson has a reputation for being the office Linux nut. No small feat, when you consider that everyone at Anchor is a Linux nut. He works as a Systems Admin with Chris and Ryan. How did you come to be working at Anchor? “I was attending PyCon AU in Tasmania. I saw the Anchor banner next to the food table. When I got back, I checked out their company blog. I’d never worked on high-availability stacks or a lot of the other technologies mentioned and I thought that would be fairly interesting. So I applied for a job. I’ve been here since January. What did you do before working at Anchor? I spent the last 7 years working in an IT position in the education sector in Armidale. I’m from Tamworth…

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