Ubuntu Server and Ubuntu Desktop Support
Ubuntu Server Edition
Lean, fast and powerful, Ubuntu Server delivers services reliably, predictably and economically – and it easily integrates with your existing infrastructure.
Recommended Minimum System Requirements:
Ubuntu Desktop (GUI) Installation
* 1 GHz x86 processor
* 512 MiB of system memory (RAM)
* 5 GB of disk space (for OS files; consideration should be given to the (often very large) size of user files that will occupy the /home directory)
* Graphics card and monitor capable of 1024x768
* CD-ROM drive
* Sound support
* Internet access
Ubuntu Server (CLI) Installation
* 300 MHz x86 processor
* 128 MiB of system memory (RAM)
* 1 GB of disk space
* Graphics card and monitor capable of 640x480
* CD-ROM drive
Ubuntu Netbook Edition
*Intel Atom processor @ 1.6 GHz
*512 MiB of system memory (RAM)
*4 GB of disk space
*Screen of 1024x600 resolution
*Graphics chipset with support for visual effects
Kernel Differences:
* The Server Edition uses the Deadline I/O scheduler instead of the CFQ scheduler used by the Desktop Edition.
*Preemption is turned off in the Server Edition.
*The timer interrupt is 100 Hz in the Server Edition and 250 Hz in the Desktop Edition.
[Note]When running a 64-bit version of Ubuntu on 64-bit processors you are not limited by memory addressing space.
How do I partition the Ubuntu server?
Partitioning a server's disk space is more art then science. Using Logical Volume Manager (LVM) and RAID hardware or software allows greater flexibility in terms of disk layout. Partitions using LVM can be easily expanded to meet future requirements.
A common partition configuration is to have /home, /opt, /usr, /var, /tmp, and /srv on separate partitions from /. Depending on the services provided by the server and where you wish to store your data will determine how much space each partition is alloted. Ubuntu complies with the Filesystem Hierarchy Standard, where you will get additional information on which is what.
As an example we have a home web server that will also serve files to Windows clients using Samba. The server has one 250G hard drive and will be partitioned:
/ = 5G
/home = 20G
/opt = 5G
/usr = 30G
/tmp = 2G
/var = 50G contains /var/www which will be served by Apache.
/srv = 50G contains /srv/samba served by Samba.
93G = Unpartitioned space can be alloted where necessary using LVM.
Kernel Requirements
The minimum requirement for the server kernel is that your architecture supports PAE (which allows addressing of more than 3G of RAM
Depending on the installation method, a proper kernel is installed for your system. It is also possible to install a different kernel after installation. For example, if you have installed Ubuntu Server Edition then decide to install a wireless network card, it may be better to use the generic kernel and modules. The generic kernel can be installed from a terminal by entering:
sudo apt-get install linux-generic linux-restricted-modules
Ubuntu, as all Unix or Linux system, does have a root account, it is just that the password to log into it is not set by default. This is done on purpose as explained below.
Why doesn't Ubuntu provide a root account by default
Ubuntu implements a role-based administration model with no default root access. Other Linux distributions typically provide this root access but role-based administration allows for better security, error prevention and auditing. This is particularly useful on systems where more than one user might have been given root access, as in a traditional model. Privileged user that are part of the admin group can issue commands as if they were root using the sudo command, including "sudo su" which will bring them to a root prompt. The /etc/sudoers, which should be edited with the sudo visudo command, allows to specify finer execution rights for particular users or groups. All sudo action are logged as the original user, therefore allowing to trace who has done what and when.
It is also much more complicated for a remote attacker to target a brute force password attack on an account when it does not know the name the account will use by default. The root account is common to all UNIX/Linux platforms, the name you will give to you privileged account is not likely to be.
