Entries Tagged 'Hardware' ↓

Linux Software RAID 5

So, I’ve been using MythTV recently. I have my master backend upstairs, with all of the storage. And then downstairs is the slave backend with the three tuner cards. Soon after setting all of this up, I found that I was going to run out of disk space for recordings pretty quickly.

Therefore, I bought three 750GB hard disks to complement the one 750GB disk that I had already. And I decided to get a bit of RAID 5 set up. I didn’t trust the fake raid card in my server box, or even believe it was supported in Ubuntu. So I had a look into software RAID. It looked pretty good, so that’s what’s setting up now.

Scan Packaging

I was a bit shocked to see the packaging Scan.co.uk sent the hard disks in, as you can see. There is also a hard drive mounting kit for a optical drive bay in there as well. Luckily, nothing seems damaged, so let’s hope it stays that way!

Hard Disks in Server

And this is the process I am following to get all of this organised and set up…

  1. Connect up all the new hard disks
  2. Format the new disks and set the RAID flag
  3. Create a new blank RAID array with the three disks
  4. Transfer all the old data onto the array
  5. Change the /var/nas mount point to the new array
  6. Format the old disk
  7. Add the old disk to the array and expand the array
  8. Expand the file system

It’s taking time, but it’s coming along. I’m at step #7, and it looks like it’s going to take a while. It’s at 3.9% and has an estimated time of 869 minutes left. Should give me a chance to do something useful.

Anyway… On to some revision. See ya.

Soldering Clap Switches

After watching recent Systm episodes, I decided that I would try and get into electronics. The most specific part that I decided I wanted to get into was the AVR programming. But before I get to that, I decided that it would be a good idea to learn how to solder first!

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Off I went to a Maplin store. You walk into maplin and you are instantly greeted with millions of electronic things, of which I didn’t know what they were. Walking around there, for a while, I discovered some electronic kits. These “make your own” kits are manufactured by Velleman, and I can recommend them.

So after browsing through the many different kits, I ended up choosing a Clap activated switch. Whilst I was there, I grabbed a soldering iron stand, as I already had the soldering iron + solder.

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Opening the kit presented me with millions (ok, 20) resistors, and a bunch of other electronic parts. Two days later, and the solder sucker having to be used occasionally, the kit was finished. One thing I forgot to purchase was a transformer to plug it in with. After visiting maplin I came home and found the transformer was faulty. It is one of those changeable voltage transformers. This one, however, would only work when set to 6 volts. After getting a replacement, finding that it was faulty too, buying a different one instead, I finally got the clap switch to work.

And am I surprised that it worked first time? Well… Yes!

And where will I go from here then? Read on…

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Vodafone 3G card in Ubuntu

Update: Since writing this blog entry many developments have happened with mobile internet under linux. These days you can just plug and go. NetworkManager will even help you find the right settings. However, I haven’t tested this particular mobile broadband pcmcia card with recent versions of Ubuntu, but assume that it works well. Leave a comment if you have any problems :)

First off, I realise that I haven’t posted a blog entry in a while now. I don’t know why I haven’t, as I’ve had plenty of time, it being the summer holidays and all. I always find my self wanting to do so much stuff in the summer holidays, and somehow turn up doing hardly anything. ‘Tis a shame.

Anyway…

After reading this mailing list post on ubuntu-uk, I was surprised these 3G datacards actually worked under ubuntu. Therefore, I instantly zoomed off to ebay and purchased one for £34 + postage. I made sure it said unlocked in the ebay listing, as I currently have a virgin mobile sim card and didn’t want to waste/switch to vodafone.

So the datacard turned up and I popped my phone SIM in it. Following the guide that was written in the mailing list, I configured it. This was using kppp. So I made everything was in there right and tried to connect. One problem though. Everytime I tried to connect kppp would lock up instantly. “Ah dear”, I though.

After much researching, I managed to set up the datacard using gnome-ppp, which is equally, if not more, easier to set up the datacard in. And here is a little guide I’ll write in full for you…

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Servers and Whatnot

So I’ve been on a little fun into setting up a webserver. Using an old computer which uses a shuttle case + motherboard. This case and motherboard has been through a lot. Stuff taken in and out loads.

And the fan failing. That was fun. It kept overheating and after much playing around, we found that the fan on the cpu heatsink had died. Shuttle being nice and kind when they designed this heatsink, made a size fan that you can’t get anywhere. Instead, I got a generic case fan and duct taped it to the heatsink! Clever, eh?

So my server. What is it serving? Well, it’s backup server. Thanks to the backuppc package, all the computers will be backed up in my house. Every week a full backup is done. Followed up by a incremental backup each day. Backuppc is also very clever. If there are files that are the same across backups and computers, the file will only be stored once. I can’t backup my whole house yet though. This is because of the hard drive in the server. It’s only a 120GB one. That means I’m currently only backing up one computer as a test.

What else is my server serving? SSH. The first thing I did when I set up the server was install SSH. This is for two reasons. The server is now on top of a shelf somewhere else in the house with only power and an ethernet cable attached. SSH is my means of remote access. The other reason is so I can have a nice SSH tunnel when I go to sixthform in September. No more annoying school filters to me :-) Another part of my SSH server is a key based authentication. I decided that I didn’t really want to put my server out on the internet, if someone was able to bruteforce the password. Therefore, I have set up key based authentication and completely turned off Password authentication.

Quotas. I also managed to set these up. Just as a play around really. It was pretty simple to do:

  1. sudo apt-get install quota
  2. Open up fstab and pop in the usrquota option to the partitions that need to be quotaised
  3. Restart
  4. sudo edquota -u username
  5. The quota config for that user will show up. Under the blocks and inodes column, you are able to see what the current use of that user is.
  6. You are then able to edit the number of blocks (1,000 blocks = about 1MB) that the user can make under the first hard and soft columns.
  7. The second quotaing is the number of files which can be set under the second hard and soft columns
  8. Save and quit. You’re set!

What’s the difference between hard and soft quotaing you ask? From what I’ve read around the internet, a soft quota is one that limits the user slightly. The user is allowed to go over the soft quota. But only for a limited time, before they have to delete the files. The hard quota is a strict quota. You hit that quota, and that’s it. Delete the file or be able to do nothing!

And of course, to do my bit, my server is folding proteins. Slowly but surely…

Folding stats