Linux Installation
In this blog we will discuss how to do installation for new machine and what are the basic requirements for installation.
System Requirements
Architecture
These instructions are for installing Red Hat Enterprise Linux 6 (RHEL6) on an IA-32 system (i.e., a 32-bit Intel- or AMD-based system) and Opteron 64-bit systems (x86_64).
Minimum Memory
Red Hat recommends for 32 bit a minimum of 1GB memory/logical CPU, and for 64 bit a minimum of 1GB of memory, 1GB/logical CPU. At SLAC, RHEL6 has been successfully installed on systems with 512 MB, but such systems have a tendency to bog down badly due to excessive swapping when too many applications are open at once.
Minimum Disk Space
OCIO recommends a minimum disk size of above 12 GB, and a minimum root partition ("/") size of about 9 GB.
CDROM Drive
Red Hat does not include a floppy version of the boot images for RHEL6. Your system will need a boot- capable CDROM drive, or BIOS which knows how to do PXE boot.
Hardware Support
Naming convention for network interfaces
Traditionally, network interfaces in Linux are named eth[X]. However, in many cases, these names do not correspond to actual labels on the chassis. Modern server platforms with multiple network adapters can encounter non-deterministic and counter intuitive naming of this network interfaces.
Red Hat Enterprise Linux 6.3 introduces biosdevname, an optional convention for naming network interfaces. Biosdevname assigns names to network interfaces based on their physical location. Note, however that biosdevname is disabled by default, except for a limited set of Dell systems.
USB 3.0
The implementation of version 3.0 of the Universal Serial Bus (USB 3.0) specification is a fully supported feature in Red Hat Enterprise Linux 6.3. USB 3.0 support was previously considered a Technology Preview in previous releases.
CPU and Memory Hot-add
On Nehalem-EX, hot-adding of CPUs and memory is now fully supported in Red Hat Enterprise Linux6.3. Note, however that the hardware must also support hot-adding. Damage may occur from an attempt to hot- add CPUs or memory on hardware without support for hot-adding.
Planning the installation
Before any software can be installed, the computer has to be able to recognize the hardware it will be using. The installation process will ask you about your hardware, so have this data ready before you start.
You should know the make and model number for each of the following pieces of hardware, if you have them:
- SCSI controllers
- Networkinterfacecards(NIC)
- Videocards
- Soundcards
- PackagestoBeInstalled
Red Hat Linux comes conveniently bundled with an array of pre-configured software packages. Most likely, you will not need to install all of these packages, and for security reasons (or office policy) it is a good idea not to. Your boss might not appreciate the office network being used to serve personal Web pages from each employee’s installation of an Apache Web server. Also, every computer on your network doesn’t need to run the innd network news service. Limit the packages you install to only the ones you need. If other packages are required later, they can be installed easily with the rpm tool.
Partitioning the Drive
It is recommended that you make several partitions when preparing your hard drive to install Linux. This is a good idea for various reasons. First, Red Hat Linux runs two filesystems: a Linux native filesystem and a Linux swap space. Second, if you want to install Red Hat Linux and another operating system on the same computer, you will have to create separate partitions for each.
Stability and Security
The Linux native file system is usually divided among many hard drive partitions. The recommended configuration is a separate partition for each of these directories: /, /usr, /tmp, /var, and /home as well as separate partitions for corporate data, database services, and even the Web and FTP sites if they are expected to be large.
Partitioning the hard drive in this manner keeps system, application, and user files isolated from each other.
This aids in protecting the file space that the Linux kernel and the rest of your applications use. Files cannot grow across partitions.
Therefore, an application that uses huge amounts of disk space, such as a newsgroup server, will not be able to use all of the disk space needed by the Linux kernel. Another advantage is that if a bad spot develops on the hard drive, it will be easier to restore a single partition than the entire system. Stability and Security is improved.
Multiple partitions give you the ability to mount some filesystems as read-only. For example, if there is no reason for any user (even root) to write to the /usr directory, mounting that partition as read-only will help protect those files from being tampered with.
How much space is required?
According to your needs and the function of the computer you should size your Linux partitions. For example, a mail server will require more space for the /var directory because the mail spool resides in /var/spool/mail. You may even want to create a separate partition just to accommodate /var/spool/mail.
Linux Swap Space
Normally, Linux can use a maximum 4GB of swap space. This 4GB can be spread over a maximum of eight partitions. Note that each swap partition is restricted to a maximum of 2GB. There is no authoritative formula for deciding how much swap space should be made, but you can make an estimate based on the typical UNIX thumb rule, swap space should be double or 1.5 times the amount of RAM. Disk space is very cheap compared to RAM.
BIOS Limits
Be aware that some computers, built before 1998, may have a BIOS (Basic Input/Output System) that, at bootup (under DOS), limits access to hard disks beyond their 1024 cylinder. A common effect of this problem is your computer’s inability to see any partitions past the first 512MB of disk space at boot time. If this limitation affects your computer, do not place any bootable partitions after this barrier or the BIOS will not be able to access them and your Linux operating system will not be able to load.
Install options
The Red Hat Linux installation program has the ability to test the integrity of the installation media. It works with the CD, DVD, hard drive ISO, and NFS ISO installation methods. Red Hat recommends that you test all installation media before starting the installation process, and before reporting any installation-related bugs (many of the bugs reported are actually due to improperly-burned CDs).
To test, type linux mediacheck at the boot prompt. While most present-day computers are able to start the installation process by booting directly from the first Red Hat Linux distribution CD, some hardware configurations require the use of a boot diskette. If your hardware requires a boot diskette, you should be aware of the following changes. As with previous releases of Red Hat Linux, these image files can be found in the images directory on the first installation CD.
If you are performing anything other than an installation from an IDE or USB device, you will be asked to insert a driver diskette created from one of the following image files:
drvnet.img - For network installations
drvblock.img - For SCSI installations
pcmciadd.img - For PCMCIA stallations