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fail Archives - AWS Managed Services by Anchor

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…

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Weathering the ClickFrenzy Storm

By | Company News, Technical | No Comments

It was touted to be the online sale to stop the nation. In reality, for most, it turned out to be the online sale which broke the Internet. At a time when bricks and mortar shops are seeing a decline in sales — this was a real opportunity to regain some ground against international competition. And for some, they did. But for many of the retailers getting in on the action – it was nothing more than an abysmal failure. It doesn’t take too much to just see how widespread the performance and reliability problems were last night; social media was quick with the complaints rampant on the #ClickFrenzy hashtag and both #ClickFrenzyFail and #ClickFail were trending. On Facebook, a group “ClickFrenzy fail” was created and quickly gathered thousands of…

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Seven signs of a bad sysadmin

By | Company News, Technical | 3 Comments

The title for this post was originally going to be “things that will get you fired from Anchor”, but we realised they might be more generally applicable and actually more cerebral that they first appear. These aren’t just any old sysadmin WTFs. To be sure, some are serious “what ever made you think that could possibly be a good idea!?” material, but most are a bit more subtle and deep seated. Some of them are massively widespread and we’d be remiss to not acknowledge that it’s hard to fix – being sysadmin is suffering, and it can be an act of heroism to dig yourself out of someone else’s hole to get on top of things. Rebooting as an instinctive reaction to problems Sometimes it’s just so tempting to reboot…

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Why web developers don’t make good system administrators

By | Company News, Technical | 2 Comments

Straight off the bat I would make something clear:  I have a lot of respect for software and web developers.  Being able to write clean, intelligent and efficient code is certainly one of the more difficult aspects within this industry. With this in mind, I think that anyone who is able to write a consistently high level of code based on often sketchy requirements and delivering this within the usual time pressures of business should be awarded some kind of medal. That said, I can say with some confidence that we have the pleasure of working with some of the very best software and web developers both locally here in Australia as well as abroad. Further to this, I can also add quite unreservedly that software developers really don’t make…

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Monitor your servers like it’s 1996

By | Technical | No Comments

Whilst I’m a fan of using percentages for my disk space checks, sometimes an explicit size is more appropriate. So, you’d expect the following to work nicely: $USER1$/check_disk -w 5G -c 1G -p /data/foo If you don’t actually test that this works (by artificially filling your disk and seeing what happens), you may be dismayed to find that you only get alerted when the disk has 5MB of free disk space. Why is this? Because Nagios, despite the fact that nobody has sweated the megabytes for about a gazillion years, doesn’t support ‘G’ as a suffix for thresholds. Oh, it’ll make a good show of pretending — after all, the output formatting options have ‘GB’ as an option — but nope, for your thresholds it’s “5000M” all the way. ROCK…

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I always knew webmin was arse, but this…

By | Technical | No Comments

This is the output of iptables -L on a webmin-managed box I just saw: Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all — anywhere anywhere ACCEPT all — anywhere anywhere ACCEPT tcp — anywhere anywhere tcp flags:ACK/ACK ACCEPT all — anywhere anywhere state ESTABLISHED ACCEPT all — anywhere anywhere state RELATED ACCEPT udp — anywhere anywhere udp spt:domain dpts:1024:65535 ACCEPT icmp — anywhere anywhere icmp any ACCEPT tcp — anywhere anywhere tcp dpt:ftp ACCEPT tcp — anywhere anywhere tcp dpt:ssh ACCEPT tcp — anywhere anywhere tcp dpt:smtp ACCEPT tcp — anywhere anywhere tcp dpt:domain ACCEPT udp — anywhere anywhere udp dpt:domain ACCEPT tcp — anywhere anywhere tcp dpt:http ACCEPT tcp — anywhere anywhere tcp dpt:pop3 ACCEPT tcp — anywhere anywhere tcp dpt:imap ACCEPT udp — anywhere anywhere…

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When HA won’t play the way you want it to

By | Technical | No Comments

In an ideal world every service would support High Availability and Load Balancing, would scale up easily and cleanly and all of us systems administrators would be paid bucketloads to play golf all day while the computers did all the hard work. To quote Dylan Moran of Black Books fame, “Don’t make me laugh…bitterly”. I’ll cut to the chase – sometimes you have to really shoehorn technologies to do what you want. Fortunately I love doing this, and the technologies of today’s article are virtualised Windows 2008 on Xen, and Oracle XE 10g. Neither likes to play ball, for a few reasons: Generally speaking, when you virtualise an OS you want to have para-virtualisation drivers enhancing the hardware support. Open Source Xen has PV drivers, but they are not signed…

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