We’ve updated our dedicated server range. Our entry level hardware RAID server has had a RAM and CPU boost to 2.5Ghz Ivy bridge and 16GB of RAM. Our RAID10 servers have been boosted to 32GB of RAM or 128GB of RAM and we’ve now got some machines with 256GB of RAM available.

We can also by arrangement now offer VMs with 120GB of RAM (we’re using the 128GB dedicated servers to expand the next phase of our virtual server platform).

We’re now running a mirror for the Raspberry Pi download server and the Raspbian apt repository on a Raspberry Pi.

The first problem was obtaining a Raspberry Pi as buying one was tricky: firstly the online shops were down then the queue for a Pi was rather long. As any banker can tell you occasionally crime does pay so I abducted Mooncake, a cat which owns Liz and Eben. I then ransomed the feline back in exchange for a Raspberry Pi.

The hardware setup starts with a power supply with an IEC14 connector connected to the masterswitch for remote power cycling. This PSU connects to a powered USB hub, with a USB lead connecting to the power connector on the Raspberry Pi. The Pi is then connected back to the hub on the data cable with a 1TB USB external hard disk attached to that. There’s a 100Mbit ethernet cable which connects up to the core Mythic Beasts network and out to the Internet. Technically the switch port on the other end is 1Gbit but the Raspberry Pi isn’t fast enough to use that.

The yellow fibre in the background is a very large Internet exchange with over a terabit of bandwidth, the Pi isn’t connected directly (that’d be too stupid even for us) and the packets travel from the Pi to the exchange a couple of feet away via another building. However with LONAP and LINX within 2ms and AMSIX a mere 8ms away it’s still rather well connected.

The software setup on the Pi is fairly straightforward. We started with the Debian squeeze image, ssh / apache enabled, munin enabled (graphs here). We’ve changed the password (obviously), the ssh keys (shipping the same ssh key on every OS image isn’t optimal), and moved /var/www and /var/log to the USB disk so as not to fill the SSD card. rpi-update was needed to make the USB/network setup stable under load as the initial image kept crashing. We also set the RAM split to 224MB for Linux as we really aren’t using the GPU.

It’s up and running both IPv4 (93.93.128.128) and IPv6 (2a00:1098:0:80:1000:13:0:3), as the core Raspbian server is also running IPv6 and the main Raspberry Pi server is also IPv6 at present this machine has seen more than 50% of its traffic over IPv6. I suspect this will change as people download images from it though.

At present the Raspberry Pi is devoting nearly half its CPU to drawing munin graphs so I need to benchmark the new Raspbian distribution to see if the hard float debian build improves the anti-aliasing, as presently all the calculations are done without using the FPU on the arm core in the Pi. Benchmarking suggests that we can deliver 35-50Mbps of file downloads reasonably comfortably at present.

Is this sensible? We’ve had a few customers ask us if the Raspberry Pi would be a sensible device for hosting on as it’s very cheap and very low power. Unfortunately it’s also very slow for this kind of application and the supporting hardware is very bulky. The i7 quad core mac mini occupies less space than the Pi + hub + disk + PSU, uses about fives times as much electricity, costs about five times as much once you include the supporting hardware but is hundreds of times faster. So revolutionising the hosting industry isn’t going to happen with the Raspberry Pi, at least not until they build a PoE one with gigabit ethernet and more RAM.

It’s not currently sensible to do this with shelves full of Raspberry Pis because the performance per Watt isn’t good enough. But we’re working on it.

Thanks go to Liam Fraser and Mike Thompson for adding us to the official mirror lists for the Pi and Raspbian. Additional thanks go to Eben and Liz for paying the ransom fee of one Raspberry Pi in exchange for the safe return of Mooncake who looks a lot like Raffles.

This evening I joined Eben & Liz Upton at the Nominet Internet Awards in my role as a contributor to the Raspberry Pi project. We were moderately surprised when the project won the Outstanding Contribution award. We’d like to offer our congratulations to everyone nominated for an award and to thank Nominet for an excellent evening.

People with excellent eyesight may be able to spot me in this photo taken by Dr Black.

All Mythic Beasts domain registrations include access to our DNS service, which includes a number of powerful features.  One of these is an API that allows you to programmatically make changes to the DNS records for your domain.  This has a number of uses including:

• Automating DNS-based failover
• Scripting the redirection of requests to another server to display a holding message during maintenance periods
• Implementing “dynamic DNS” so that you can have a static hostname for a dynamically allocated IP address

The DNS API provides a simple, HTTP-based API, that is designed to be trivial to script.  We’ve recently made some improvements to the API.  The first is that where multiple commands are included in a single request, they are treated as an atomic transaction, meaning that they either all succeed or all fail, and there is no risk of the changes being made live with only some of the commands completed.  This means that you can change a DNS record by including a DELETE and an ADD command in a single request.

The other change is that the API now makes use of HTTP error codes to reflect the results of the transaction.  If you get a 200 response, all of the commands succeeded.  If you get anything else, then none of the commands will take effect.

You can find full details of the API, including some sample Perl code on our support pages. It’s also pretty easy to script it on the command line. Here’s an example of how to change a CNAME record using cURL:

curl --data 'domain=example.com&password=s3cr3t&command=DELETE www 86400 CNAME live.example.com.&command=DELETE www 86400 CNAME backup.example.com.'   https://secure.mythic-beasts.com/control/fcgi/customer/primarydnsapi

There’s a well publicised bug in the linux kernel which makes it unhappy with leap seconds and usually Java and Mysql. If you’ve a linux box running at high CPU for no explicable reason after the leap second at the weekend you were probably affected.

The fix is,

/etc/init.d/ntp stop
date; date `date +"%m%d%H%M%C%y.%S"`; date
/etc/init.d/ntp start

This is what it did to the power monitoring in one of our racks with a large number of affected machines.

There is a reason we allocate the whole power allocation for a server and not just the typical idle usage.

100 years ago Alan Turing was born, in his sadly short lifetime he achieved a number of fairly impressive things, broke the enigma cipher, invented modern computing and invented the Turing test. On his day off he ran up and down the river in Cambridge and narrowly missed a place in the Olympic marathon team.

We haven’t done anything quite as impressive as that, although to be fair I don’t think anyone else in the last century has either. However some time ago at the Cambridge Beer Festival team Mythic entered a code cracking challenged based on a piece of ciphertext printed on a poster.

BLEQXVXEKPNRMWBRMVMVERNMWMZNQTTMRKMTMRHP

This is a substitution cipher which team Mythic cracked on the first day. You can decipher it with this perl one liner,

echo ‘BLEQXVXEKPNRMWBRMVMVERNMWMZNQTTMRKMTMRHP’ | perl -pe ‘tr/NMWZQTRKHPEBLXV/sonfidtcukaemlb/;’

which outputs

emailblackstonetobobatsonofsiddotcodotuk

We did, and we now have to get onto the more difficult task of finding a convenient day to have a barbeque and drink the beer we won.

If you think that working for a company that goes to beer festivals and solves problems by writing little bits of code is fun our jobs page is here: Mythic Jobs. If you’re running a web facing company and thinking that this is terribly clever you might want to think about our managed hosting.

Behind the scenes we’ve been expanding and improving our VDS platform. We’ve just added a second cluster (Telecity HEX) that you can now order VMs in and we’re about to add a third cluster (Cambridge) too. You’ll be able to specify which zone your virtual server runs in if you have a preference and each one is independently routed.

We’ve had a long association with the Cambridge Cycle Campaign and Cyclestreets. Cyclestreets are borrowing a 64GB VM in our HEX cluster to run some of their data import jobs and to test out how well it works. Shortly after that we’ll be launching bigger VM sizes, 16GB, 24GB, 32GB, 48GB, 64GB and 80GB with corresponding disk and bandwidth increases. Initially these will be available in the London zones only (SOV/HEX) but we expect to follow through with Cambridge in the near future.

So I had reason to transfer 350GB of data from a server hosted by Mythic Beasts to a USB drive in order to back up and ship the data to a bandwidth deprived customer. For reasons of my convenience I thought I’d do this from my home office where I have a 10Mbit ADSL connection provided by a small reputable and non bargain basement ISP and a 60Mbit connection provided with an entirely different technology. I split the source files roughly 2:1 between the connections and downloaded them with rsync tunnelled over ssh. Over the next 26 hours the download ran, 99.6GB over the DSL line (average speed 8Mbits),150GB over the cable (average speed 12Mbits).

I’ve taken the bandwidth graph from the server and included it above. The blue box is the DSL line data, the wavy line the cable. You’ll notice the DSL line runs flat out the whole time with it’s performance never wavering, the cable is clearly limited by congestion. This isn’t an issue on the server side – we’ve 100Mbits from the server up to to the router then 1Gbit out to the peering exchanges (LoNAP and Edge-IX) where we pick up the DSL and cable providers.

The main difference here is the incentive scheme. My DSL provider gives me a bandwidth cap and charges me for additional bandwidth over that limit. Consequently they have an incentive to make my line as fast as possible because that makes it easier for me to pay them more. It also means the only other users of the network who are using large quantities of traffic are paying their fair share which provides the money to upgrade the network. My cable connection is ‘unlimited’ which means performance is constrained by congestion caused by other users. The flat-lines are caused by the rate limiting confusing ssh and the connection essentially stopping until I had to intervene restart the transfer. I’ve included these because fast though 60Mbits may be, I’m not going to sit and babysit for the full 350GB download to complete.

This is why servers supplied by Mythic Beasts come with fast connections, bandwidth allowances and excess fees. We want to make your connection as fast as possible so you can easily spend more money with us.

Yesterday Mythic Beasts and selected friends went to the Cambridge beer festival. Whilst there we saw a poster put up by the Son Of Sid brewery for a beer called codebreaker with a mysterious set of non-sensical characters at the bottom.  It took about a minute of staring knowingly before one of us said ‘well it’s not a substitution cipher’, followed by ‘I wish I had a laptop with me’ and before we knew it we had a crack team trying to break the cipher.

If you’d like to have a go yourself we suggest you get down to the beer festival, the breweries twitter feed says you have until Saturday to work it out. At the end there’s going to be a draw from all the successful entries to win a polypin of beer.

I don’t think we managed to save the world from a Hollywood style alien invasion but we had fun and drank beer at the same time.

EDIT: The official brewery twitter feed says,

Bob Mitchell ‏@sonofsidbrewery

One entry so far in the codebreaker competition @cambeerfest
12:27 PM - 22 May 12 via web · Details 

that was team Mythic.

A customer wanted to use Django (this is a web application framework for the Python language), but found it wasn’t installed on their hosting server (which happened to be sphinx in this case). A couple of emails to support@mythic-beasts.com later, and they were up and running within 24 hours.
The moral of this story: if you’re trying to do something with a Mythic Beasts service, and seem to have hit a brick wall, do get in touch. If it’s at all sensible, we’ll try to make it possible, and if it’s not sensible, we’ll let you know!