Dual-Booting Issues

If you are new to Linux, you may not be ready to commit to a complete system with Linux when you just
want a test drive. All distributions of Linux can be installed on only certain partitions of your hard disk while leaving others alone. Typically, this means allowing Microsoft Windows to coexist with Linux. So you  can install Linux and Microsoft windows on same machine without any problem between the two.

Because we are focusing on server installations, this post will not cover the details of building a dual-booting system; however, anyone with a little experience in creating partitions on a disk should be able to figure this out. But anyways i will be including this in my later posts. If you are having difficulty, you may want to refer
to the installation guide that comes with your distribution.

Some quick hints:

• If a Windows 95 or Windows 98 partition currently consumes an entirehard disk as drive C:, you can use the fips tool to repartition the disk. Simply defragment andthen run fips.exe. 
  

• If you are using Windows NT/2000 with NTFS and have already allocated all the disk with data on each partition, you may have to move data around a bit by hand to free up a partition. 
  

• Don’t bother trying to shrink an NTFS partition, though; because of its complexity, it doesn’t like being resized, and doing so will lead to corruption.
  

NOTE:-

• From the perspective of flexibility, NTFS doesn’t sound like a good thing, but in reality it is. If you have to run a Windows server, use NTFS.

• You may find using a commercial tool such as Partition Magic to be especially helpful, because it offers support for NTFS, FAT32, and regular FAT, as well as a large number of other file system types. Its user interface is also significantly nicer than fips.

• If you’re going to be installing a dual-boot system, install Linux last. If you install Windows last, it will clobber the boot information for your Linux system. If you install Linux last, it will recognize that you have Windows installed and let you choose which one you want to boot by default. 

Related Posts:-

• Installing Linux in a Server Configuration
• Performing Preinstallation Evaluation
• Server Design

Configuring a Secure System

Linux Administrator"s most important duty is the , security of the computer and data integrity.

What does this mean?  The system administrator’s most important task, first and foremost, is to make certain that no data on the machine or network are likely to become corrupted, whether by hardware or power failure, by misconfiguration, or by malicious or inadvertent intrusion from elsewhere.

Everyone involved in computing are aware of the increasing serious attacks upon machines connected to the Internet. The majority of these have not targeted Linux systems, but that doesn’t mean that Linux systems
have been entirely immune, either to direct attack or to the effects of attacks on machines running other operating systems.

In one such Distributed Denial of Service (DDoS) attack aimed at several major online companies, many of the “zombie” machines(Machines unknowingly used to spread malware without its owners consent ) — so that the vandals could employ thousands of machines instead of just a few — were running Linux that had not been patched to guard against a well-known security flaw. In the various “Code Red” attacks of the summer of 2001, Linux machines themselves were invulnerable, but the huge amount of traffic generated by this “worm” infection nevertheless prevented many Linux machines from getting much Web-based work done for several weeks, so fierce was the storm raging across the Internet. While these infection did not corrupt Linux machines as it did those running a different operating system.

 Security can be as simple as turning off unneeded services, monitoring the Red Hat Linux security mailing list to make sure that all security advisories are followed, and otherwise engaging in good computing practices to make sure the system runs robustly. Or it can be an almost full-time job involving levels of security permissions within the system and systems to which it is connected, elaborate firewalling to protect not just Linux machines but machines that, through their use of non-Linux software, are far more vulnerable, and physical security — making sure no one steals the machine itself! For any machine that is connected to any other machine, security means hardening against attack and making certain that no one is using your machine as a platform for launching attacks against others. If you are running Web, ftp, or mail servers, it means giving access to those who are entitled to it while locking out everyone else. It means making sure that passwords are not easily guessed and not made available to unauthorized persons.

 So your job as a system administrator is to strike just the right balance between maximum utility and maximum safety, all the while bearing in mind that confidence in a secure machine.

There are  many tools that Red Hat Linux provides to help you guard against intrusion, even to help you prevent intrusion into non-Linux machines that may reside on your network. Linux is designed from the beginning with security in mind, and in all of your tasks you should maintain that same security awareness


Related posts:-

• Installing and Configuring Servers
• Installing and Configuring Application Software
• Creating and Maintaining User Accounts
• Backing Up and Restoring Files
• Monitoring and Tuning Performance

Monitoring and Tuning Performance

On a modern stand-alone system, Linux is pretty quick, and if it isn’t, there’s something wrong — something that is up to the system administrator to fix. You might have a number of people using the same fileserver,
mail server, or other shared machine, in which small improvements in system performance can mean a lot.

System tuning is an ongoing process carried by a variety of  monitoringtools. Some performance decisions are made at installation time, while others are added or configured later.

Proper monitoring can detect a misbehaving application that might be consuming more system resources than it should or failing to exit completely on close. Through the use of system performance tools you can determine when hardware — such as memory, added storage, or even something as elaborate as a hardware RAID — should be upgraded for more cost-effective use of a machine in the enterprise. Possibly most important, careful system monitoring give you an early idea when a system component is showing early signs offailure, so that any potential downtime can be minimized.

Careful system monitoring and built-in configurability of Linux allows you to squeeze the best possible performance from your existing equipment, from customizing video drivers to applying special kernel patches to simply turning off unneeded services to free memory and processor cycles.

Backing Up and Restoring Files

Until equipments becomes absolutely failure proof, and until people lose their desire to harm the property of others for personal benefits (and, truth be known, until system administrators become perfect), there is always a need to back up important files and data so that in the event of a failure of hardware, security, or administration, the system can be up and running again with minimal disruption. Only the system administrator may do this.

(Because of its built-in security features, Linux may not allow users to be able even to back up their own files to floppy disks.)

Again, knowing that file backup is your job is not enough. You need to formulate a proper strategy for making sure your system is not vulnerable to disruption. If you have a high-capacity tape drive and several restore diskettes, you might make a full system backup in every few days. If you are managing a system with scores of users, It is more sensible to back up user accounts and system configuration files, from the distribution CDs. (Don’t forget the applications you’ve installed separately from your Red Hat Linux distribution, especially including anything heavily customized!)

Once you’ve decided what to back up, you need to decide how frequently to perform backups and whether you wish to maintain a series of incremental backups — adding only the files that have changed since the last backup — or multiple full backups, and when these backups are to be performed — do you trust an automated, unattended process?

A strategy should be the maintenance of perfect backups without ever needing to resort to them. This means encouraging users to keep multiple copies of their own important files, all in their home directories, so that you are not being asked to mount a backup so as to restore a file that a user has corrupted.(And if the system is stand-alone, you as your own system administrator might want to make a practice of backing up configuration and other important files.)

The chances are that even if you’re working for a company, you’ll make these decisions — all your boss wants is a system that works perfectly, all the time. Backing up is only half the story, too. You need to formulate a plan for bringing the system back up in the event of a failure. 

 RELATED POSTS:-

• Installing and Configuring Servers
• Installing and Configuring Application Software
• Creating and Maintaining User Accounts

Creating and Maintaining User Accounts

Anyone cannot log on to a Linux machine. An account must be created for each user and — you guessed it — no one but the system administrator may do this. That’s simple enough.
But there are  decisions that either you or your company must make. You might want  users to select their own passwords, which would be easier for them to remember, but which probably would be easier for an external factor to crack. You might assign passwords, which is more secure in theory but which increases the chances that users will write them down on a conveniently located scrap of paper — a risk if many people have access to the area where the machine(s) is located. You might want that users must change their passwords periodically, and you can configure Red Hat Linux to prompt users to do so.
  
And what to do about old accounts? Perhaps someone has left the company. What happens to his or her account? You probably don’t want him or her to continue to have access to the company network. On the other hand, you don’t want to simply delete the account, because it might contain some essential data which is reside nowhere else.

 There are aspects of your business that make World Wide Web access desirable, but you don’t want user"s spending their working hours surfing the Web.

The following issues and others are parts of the system administrator’s duties in managing user accounts. The administrator or his employer must establish the policies governing them— if in an enterprise, preferably in writing — for the protection of all concerned.


RELATED POSTS:-

• Installing and Configuring Servers
• Installing and Configuring Application Software

Linux System Administrator

Every computer in the world has a system administrator. It may be that the majority of system administrators are probably those who decided as to what software and peripherals would be bundled with the machine when it was shipped. That status remains because the majority of users who acquire computers for use probably do little to change in the default values. But the minute the user makes some changes in applications and decides what softwares and applications to run he becomes a system administrator. 

Such a high duty brings with it some responsibilities. No one whose computer is connected to the Internet, for instance, has been immune to the effects of poorly administered systems, as demonstrated by the Distributed Denial of Service (DDoS) and e-mail macro virus attacks that have shaken the online world in recent years. The scope of these acts of computer vandalism (and in some cases computer larceny) would have been greatly reduced if system administrators had a better understanding of their duties.

The Linux system administrator is more likely to understand the necessity of active system administration than are those who run whatever came on the computer, assuming that things came from the factory are properly configured. By its very nature as a modern, multiuser operating system, Linux requires a degree of administration greater than that of less robust home market systems. This means that even if you are using a single machine connected to the Internet by a dial-up modem — or not even connected at all — you have the benefits of the same system employed by some of the largest businesses in the world, and will do many of the things that the IT professionals employed by those companies are paid to do.

Administering your own system does involve a degree of learning, but it also means that in setting and configuring your own system you gain skills and understanding that raise you above mere “computer user” status.

By definition, the Linux system administrator is the person who has “root” access, which is to say the one who is the system’s “super user” (or root user). A standard Linux user has limitations. But the “root” user has unfettered access to everything — all user accounts, their home directories, and the files therein; all system configurations; and all files on the system. A certain body of thought says that no one should
ever log in as “root,” because system administration tasks can be performed more easily and safely through other, more specific means, which I will discuss in later posts.