Friday, November 16, 2012

My first Raspberry Pi

I bought my Raspberry Pi (with a transparent case) 2 weeks ago. Since its tiny size and low power consumption, I decided to run it in 7x24 as a light weight server.

When the Pi was just delivered, my Dad wondered its ability. Don't under estimate the configuration of it. I called it a "server" means it really fulfill my expectation.

Once I recieved it, what have I done to it:

  1. Install a the OS - Raspbian, a fork of Debian "wheezy". The procedure is pretty simple, just download the image and "dd" to a SD card. The minimum size of the SD card is 2GB, which is also what I've got in hand.
  2. Once started the Pi, it boots automatically. Though the LXDE is installed, it is not useful for me... I just change the IP to static (/etc/networks/interface), enable the SSH and all the things are done by a SSH client.
  3. There is 512MB memory for this model, but this memory also shared with the video module. I don't need graphics, so I set 32MB to it and left the remaining to the server.
  4. Up to this point the server is ready to use. But when I examine the configuration, the 'capacity' in terms of disk size is a concern. Remember I mentioned I just got a 2GB card? In fact the Raspbian itself already occupies 80%-90%. If I install more packages, it will be full very soon. One possible solution is to buy a larger SD card (say, 8GB or 16GB) and it should be enough. But it needs extra budget for me so I decided to use another method - LVM with USB drives.
  5.  I don't have spare SD card but I DO have some USB drives. It is a good idea to plug in to the Pi. There are 2x USB ports for extension usage, not only USB drivers but Wifi adpaters or even webcam can be attached to it. It can even connect a USB hub if more devices are needed to use. 
  6. I've been using LVM on Linux, HP-UX, AIX for years so it's not a different part for me. Just create a PV on USB drive, make a VG and prepare some LV (mount points), and finally do some migration. After everything has been done, the nearly full SD card is free again:
    Filesystem                       1K-blocks    Used Available Use% Mounted on
    rootfs                             1804128  479952   1232528  29% /
    /dev/root                          1804128  479952   1232528  29% /
    /dev/mmcblk0p1                       57288   16920     40368  30% /boot
    /dev/mapper/datavg-usr_lv          1511856 1238380    196676  87% /usr
    /dev/mapper/datavg-var_cache_lv     297485  190319     91806  68% /var/cache
    /dev/mapper/datavg-usr_local_lv    1032088  422500    557160  44% /usr/local
    /dev/mapper/datavg-opt_lv           126931   40389     79989  34% /opt

  7. Now a dummy server is here, I have to spend some time to think how to do with it. What I can think of so far is to make it as:
    • a web server, with PHP and hopefully mysql as database
    • a batch job server so that it can do some simple routine tasks for me
    • a monitoring server, to collect information of other devices in the same network
    • a wiki server to setup my own wiki
    • a dropbox like fileserver. (make use of  'owncloud', which is a hot topic now I guess)
    • VPN gateway (to connect to my home network safely from other places)
Once I have some idea I will post it here and share :)

(Image source from:


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