Mein Craft

If only Hitler played about with Minecraft instead of writing Mein Kampf; He might have gone on to get the German population to build crazy structures from huge cube shaped blocks instead of pushing them to flatten Europe.

I was aware of Minecraft but I’d never looked at it or realised what it was about. Somebody I know pointed me towards a PC Gamer demo of the game, which I had up and running within a few minutes.

Confronted by nothing but a vast blocky landscape I was unsure of what to do. The square sun was shining brightly through the clouds, the trees looked err.. treeish and the beach in the distance was calling me to explore. Some angular sheep wandered near by but they ran off as I approached them. The sun moving through the sky reminded me I needed to find somewhere safe before nightfall came and the monsters came out….

The first thing you’ll discover about Minecraft is that everything in the game can be dug up, destroyed or moved. This leads to some novel approaches to problems you might face in the game. For example, It annoyed me to find that every morning there were monsters always lurking around by house. My solution was to build a moat by digging a trench around my house and filling it with water. No more monsters, but now the pigs like to bathe in it all the time.

The other main concept of the game is that of “crafting”. This is the ability to create new objects by mixing together the materials you find. I was doing it by trial and error but you can find recipes on the internet to make more advanced things. Some things can only be collected with the correct tools. I needed to make sure I had a stone pickaxe to be able to mine iron ore, my wimpy wooden pickaxe just wasn’t strong enough.

Getting materials often requires lengthy trips underground. The deeper you go the more likely you might find some useful ore or rare artefact. You’ll need to stock up on torches as it is dark down there and you’ll meet many monsters hiding in the corners. If you go too deep you might break through the mantle itself and reach a layer of lava!

The beauty of Minecraft is its simplicity. Get stuff, use stuff, place stuff, don’t die. Once you’ve figured them out you can make the game into an adventure of your choosing. It doesn’t take long before your brain starts coming up with crazy ideas you know you’re going to try. For example, I kept getting lost and it would take forever to find my way home, often being chased by monsters. I decided to build the tallest tower I could, this would then be visible from far away providing me with an easy way home. You can craft yourself a compass but that’s the easy way out. My huge engineering project filled me with pride once successfully completed.

My Minecraft Tower

My tower, visible in the distance.

I’ve since gone on to build bigger things and, by setting up my Minecraft server, have enlisted the help of my girlfriend to help with these projects (although I’ve had to switch the monsters off as she wouldn’t play with these lurking in the mines). If setting up your own server isn’t your cup of tea then there are plenty of public ones available. Be warned if you do visit though… they will make your lovingly crafted projects look pitiful in comparison!

The game is currently in a beta stage with new things being added over time. I’ve not had any problems with it as yet on my ageing system but you do need plenty of memory as it eats it by the bucket load. Since it uses Java it should run on any system with Java installed. I happily use it on my Windows XP and Ubuntu machines with no trouble.

Gotta go…. My ‘log flume down a waterfall starting at the top of a mountain’ idea isn’t going to build itself…

Ubuntu, ZFS and missing devices

I’ve used ZFS in some form or other for a few years now, starting off with the OpenSolaris based Nexenta and moving over to Ubuntu Server as ZFS matured on Linux.

Recently I’d added a couple of new drives to the pool and all was good until after a reboot. After logging in to the server I could see the pool hadn’t mounted so I attempted it manually.

It was telling me the new drives I’d added were corrupt and the pool was offline. “No Problem” I though as I could just restore from backup and re-create the pool. The only problem with that is that my last backup is 6 months old*

I then noticed that the disk assignment was wrong. My ZFS array was looking for /dev/sdb and /dev/sdc when the new disks were now at /dev/sdf and /dev/sdg.

I then remembered using /dev/disk/by-id when I initially created the pool to avoid this issue but when adding the new drives I never gave it a thought.

To fix this without losing any data I did the following:

1) Rename your zpool.cache file
mv /var/lib/zfs/zpool.cache /var/lib/zfs/zpool.cache_old

2) Now import your pool again
zpool import -d /dev/disk/by-id/ poolname
It should now look through all of your disks and mount the pool as normal with each of the disks added by id.

Taadaa! Pool mounted and a full backup has now started.

*Yes, I know. How stupid of me… ­čśŤ