Advertisment

Installing Linux

author-image
PCQ Bureau
New Update

The

PCQ June 2000 CD of Red Hat 6.2 that you are holding in your hands should be

the easiest Linux install that you've done in a long time. Essentially,

the Linux install can be demarcated into a few clear sections. Sometimes,

you could stumble over one section while the rest will be a breeze. The PCQ

CD has the Red Hat documentation that can be explored directly off the CD.

These manuals provide more in-depth information on the topics touched upon

briefly here.

Advertisment

Preparing to install

Never forget

that Murphy ("If anything can go wrong, it will") is close at

hand. So, before you start, backup all the critical data on your hard disk.

Make sure that you have approximately 1.5 GB of free hard disk space. Gather

a local Linux guru, some food, drink (not essential, but nice), and the PCQ

CD (essential and nice). It also makes sense to get two clean and freshly

formatted floppies. If this is your first time, get as many hardware details

about your machine as you can. This may also be a good time to hunt for your

monitor manual.

Installing Linux

Advertisment

Booting into

Linux is the next phase. If you have a BIOS that allows you to boot off the

CD, that's one problem solved. Enter into the BIOS and configure to boot

off the CD-ROM. If this is not possible, you could use the autoboot

application in the dosutils directory on the CD. If you're unable to use

autoboot, then you'll need to create a boot disk to start installation.

More information on this process is available in the install guide on the

CD. When the machine boots up, you'll get a prompt that reads

boot:

At this point, you could

choose a graphical install (press Enter) or choose to install in text mode

(type text and press Enter). I would recommend the text mode; it's faster

and always works straight out of the box. An example that serves to make the

point is the i810-based motherboards. The video card works perfectly fine if

you've booted into Linux, but stubbornly refuses to work during an

install. If you've installed Linux before and are sure that X Window

support for your machine (video card and monitor) works fine, then the

graphical install is a good idea.

Advertisment

The next phase involves

configuring the machine to install Linux. This includes the next few screens

in which you've to choose the language to install in (English), the

keyboard layout (US), media (local CD-ROM), and the mouse port, if you chose

graphical install. Since Linux is a powerful operating system and can

perform a variety of tasks, you've to decide if you want your machine to

act as a server, workstation, or something completely different. For most

users, a workstation install is more than sufficient. If you have special

constraints such as lack of space, you may want to go in for a Custom

install.

Partitioning your hard

disk

Now you need

to decide where you want to install Linux. There are two options at this

point. It's ideal to store and use Linux in a special partition of its

own. However, Red Hat 6.2 offers a feature by which it's possible to

install Linux on a DOS partition and work with it. Linux creates a large

file on your Windows partition and works off it. In order to boot into such

a Linux install, you'll have to use a boot disk. There's no other method

to boot into such a Linux partition, at least currently. This method is not

recommended unless there's no other alternative available. In a test

conducted at PCQ Labs, we found that not only did the install take up to

five times longer, the installed Linux system was also significantly slower

than normal, and the boot up process is painfully slow, to say the least.

Advertisment

If you have a partition that

you can delete, you could use that to install Linux. If you don't have a

partition, you'll need to create one without destroying your existing

partitions. The standard DOS utility Fdisk is unable to do such manipulation

and you may need to use tools such as PartitionMagic or FIPS (available on

the CD in the /dosutils directory). See the box "Using FIPS" for

more information.

What goes where?

During

the install, you'll need to choose the location where your Linux files are

going to be stored. This location is known as a mount point. To begin with,

ensure that the display tells you that you have free hard disk space (if you

have existing partitions that you want to install Linux over, remove them).

Linux insists on having an area designated as swap space. You need to decide

how much space to allocate for this. A rough estimate is to add a

swap partition of twice as much of physical memory your machine has.

Somewhere between 32 MB to 256 MB is a safe bet (see the article "Fine

tuning your Linux Machine", page 47 in this issue, on where to place

the swap partitions). Due to disk geometry, even though you ask it to

allocate 127 MB, the allocation may be a value in excess of this (generally

133 MB). Don't worry about that. This partition will not require a name.

Advertisment

To understand what logrotate can do....

To understand what logrotate

can do, first ask yourself what you want to do with your log files. The

table "Planning for a log processing and archiving policy" might

help you to start. The first row lists the processing and reporting to be

done, while the first column lists the files on which the processing is to

be done. Put down the different log files in column 1, tick out the log

processing of your choice, and you can come up with a policy for using

logrotate.

Let me briefly explain what

each column implies. A "yes" on column 2 indicates that you want

to retain the log file as a record, so it's best kept compressed.

Similarly, a "yes" in column 3 indicates that you merely want to

scan the file, look for the unusual, and then discard it. You might want to

mail this file to yourself or to the relevant administrator. Column 4 says

that you want to discard the file straightaway. In the sysadmin world, this

obviously doesn't qualify for best practice. Columns 5 and 6

mention the actions you want to perform before and after you do the log

processing. Column 7 is for an e-mail address to which errors during log

processing are to be reported, and column 8 indicates how often you want the

processing to be done. Note that you might want a time threshold with a

granularity of a day or choose to have a file size threshold to rotate the

logs. This table is not exhaustive or mandatory in nature-it's is merely

an example of how you would go about the policy-making exercise. So, don't

implement this, as is, as a policy. Evolve one to suit your needs.

If you're ready with a

table such as the one above, you have a policy. You can now use logrotate to

implement this policy.

Advertisment

The policy is specified using

keywords, as well as with a script-like language comprising keywords

specific to logrotate. The script is intuitive and easy to understand. By

default, most logs are rotated four times, uncompressed, before they're

removed from the system. This should explain the presence of files with the

extensions .1, .2, .3 and .4 in the /var/log directory. Take the file /var/log/messages

as an example. After a certain time period or after a certain file size is

reached (as specified in /etc/logrotate. conf), this file is renamed to

messages.1 and an empty file called messages is created to take in the new

log input. This is repeated until they're rotated four times.

Let's look at a portion of

the configuration from /etc/logrotate.conf from a standard install. The

first line mentions the name of the file for which the policy is laid out.

Notice the intuitive keywords-"monthly" indicates that the

rotation cycle is monthly, "create" specifies the permissions and

ownerships to be used when the old file is moved to another name and an

empty file is created. "Rotate 1" indicates that one rotated

logfile will be retained:

/var/log/wtmp

{ monthly

Advertisment

create 0664

root utmp

rotate 1

}

Here's a portion of the

file /etc/logrotate.d/apache-the policy for processing apache log files.

The keyword missingok implies that if the log file isn't found, continue

processing the rest. Notice the command in between the keywords postrotate

and endscript. This command is executed after log processing is done.

Surprisingly, you don't find any other instructions such as the frequency

of rotation or the number of rotations, as in the previous case. When there's

no explicit mention made, the definitions in the global configuration file

will apply.

/var/log/httpd/access_log

{

missingok

postrotate

/usr/bin/killall -HUP httpd 2> /dev/null || true

endscript

}

logrotate is typically run

once a day by the cron. If you are logged in as superuser, you would see an

entry similar to the one below in the crontab file:

0 0 * * * /usr/sbin/logrotate

The utility runs every

midnight. You can run it more often if you need to.

A good start towards

minimizing disk storage space would be to uncomment the compress option in

/etc/logrotate. conf, so that all the rotated log files are kept compressed.

Avinash

Shenoy
is a systems and network administrator at the NCBS, Bangalore,

and Gopi Garge is a technology

consultant with Exocore Consulting <www.exocore.com>

Advertisment