Chapter 6Advanced Installation

Objectives

Describe the types and structure of SCSI devices

Explain the different levels of RAID and types of RAID configurations

Describe how to install Linux from source files on CDs, USB flash memory drives, hard disks, or network servers

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Objectives (continued)

Install Fedora Linux using a kickstart file Troubleshoot the installation process Access an installed system using

System Rescue

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Advanced Storage Configuration: SCSI Hard Disk Configuration SCSI (Small Computer System

Interface): a way to connect multiple peripherals to the system

Three types of SCSI disk configurations:Parallel SCSISerial Attached SCSIiSCSI

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Parallel SCSI Configuration Ribbon cables transmit information

between hard disk and SCSI controller Terminator: prevents signals from

bouncing back and forth on a connection cable

SCSI ID: uniquely identifies devices attached to a SCSI controllerTarget IDIdentifies priority

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Parallel SCSI Configuration (continued)

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Figure 6-1: Connecting parallel SCSI devices

Parallel SCSI Configuration (continued)

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Table 6-1: Common SCSI standards

Parallel SCSI Configuration (continued) Configuration steps:

Verify all SCSI components support the same technology

Ensure that components are connected properly

Make sure system recognizes hard drives at startup

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Serial Attached SCSI Configuration Serial attached hard disks connected to

SCSI controller via serial cables with small serial connectorsMore than 60,000 devices per controller

Configuration steps:Connect hard disk to controller via correct serial

cableEnsure that hard disk is detected by system or

SCSI BIOSThe rest is performed automatically by controller

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iSCSI Configuration Internet SCSI (iSCSI): uses network cables

to transfer data to/from remote hard disksiSCSI initiator: computer connected to remote

hard disk○ Can be software or hardware

iSCSI target: remote hard disk○ Contained within remote network attached device

Configuration settings vary by manufacturerMust specify configuration settings during the

Linux installation

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RAID Configuration Fault tolerant: device exhibiting minimum

downtime after failure Redundant Array of Inexpensive Disks

(RAID): Typical implementation of fault tolerant diskCan be used to speed up access to hard diskCombines several HDDs’ storage spaceSeven RAID configurationsHardware-, software-, or firmware-based

○ Different configuration process for each type

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RAID Configuration (continued) Spanning: two HDDs seen as one volume

RAID level 0, not fault tolerantGood when need large amount of space in

single volume

Disk striping: write a portion of the information to each of multiple HDDsRAID level 0: not fault tolerantDecreases read/write time

Disk mirroring: two identical hard disksRAID level 1: fault tolerant

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RAID Configuration (continued) RAID level 2: no longer used Disk striping with parity: write portions

information to different HDDs and maintain parity informationRAID level 5: fault tolerant

○ Most common RAID configuration○ Improves on RAID levels 3 and 4

Parity bits indicate what data is where○ Intermixed on the HDDs that contain the data○ Can be used to re-generate data when HDD fails

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RAID Configuration (continued) Disk striping with parity (continued):

Requires three HDDs minimumIf any of the HDDs fail, the information can

be recovered from the other HDDsRAID level 6: uses two sets of parity bits for

added fault tolerance○ Allows two HDDs to fail simultaneously while

remaining fault tolerant

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RAID Configuration (continued)

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Figure 6-6: Organization of data on RAID level 5

Installation Methods International Standards Organization

(ISO) image: large file containing exact copy of contents of a CD-ROM or DVD

DVD is the most common and easiest method for installing Linux

Other methods for installing Linux Multiple CDsUSB flash memory driveISO image on local hard diskISO image through network server

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CD Installation

Requires six CDs First CD contains the installation

programBoot the computer using the first CD, then

make appropriate choices within the installation program

Will be prompted to insert remaining CDs when necessary

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USB Flash Drive Installation BIOS can boot the computer from a

flash memory drive Need to download Linux onto the flash

memory driveOverwrites the existing filesystem on the

driveFrom Windows, can use free utilities

○ e.g., LiveUSB CreatorFrom another Linux computer, use dd

command

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Hard Disk Installation May install Linux directly from ISO

images on hard diskMust have sufficient free space outside

partition containing ISO images Use DVD, installation CD-ROM or

bootable USB flash memory drive to start installation

Use options in the welcome screen to perform non standard installation

Installation will be text-based

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Hard Disk Installation (continued)

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Figure 6-3: Selecting a nonstandard installation method

Hard Disk Installation (continued)

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Figure 6-4: Selecting the installation media location

Hard Disk Installation (continued)

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Figure 6-5: Specifying the location of the Fedora ISO image on the hard disk

Network-Based Installations Requires installation startup DVD, CD-

ROM or bootable USB flash memory driveContains NIC drivers and programs allowing

connection to serverSelect language, keyboard setting, and protocol

Installation via one of following protocols:Network File System (NFS)File Transfer Protocol (FTP)Hypertext Transfer Protocol (HTTP)

Must configure network settings

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Network-Based Installations (continued)

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Figure 6-6: Specifying the location of the Fedora ISO image on an NFS server

Network-Based Installations (continued)

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Figure 6-6: Specifying the location of the Fedora ISO image on an HTTP server

Automating Linux Installations Deploy several Linux servers and

workstations requiring same configuration

Kickstart file: automated installation scriptSpecifies normal OS installation choicesks.cfgContains sections on system configuration,

disk partitioning, and package selection

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Automating Linux Installations (continued) Kickstart configuration: configure a new

kickstart fileUse Kickstart Configurator tool

To use ks.cfg: Place ks.cfg on CD, DVD, floppy disk, or

hard disk partitionBoot from installation startup DVDAt welcome screen, modify the boot option,

and specify ks.cfg file and its location○ Installation will run without prompting user

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Automating Linux Installations (continued)

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Figure 6-8: The Kickstart Configurator

Troubleshooting Installation Computers typically have different BIOS

configurationsInstalling on different computers is rarely the

same

Problems primarily related to hardware support or configurationTypically fixed by changing hardware

configuration

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Problems Starting the Installation Check BIOS boot order Check that battery supporting BIOS is

providing power Choose device to boot from at system

startup by pressing a special key

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Problems During Installation For graphical installation, video card and

mouse must be detected Appropriate drivers must be loadedVideo card may not be supported by mode

and resolution of graphical installation○ Install system with basic video driver

Mouse does not work○ Use text-based installation

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Problems During Installation (continued)

Linux+ Guide to Linux Certification, 3e 32

Figure 6-9: Starting a text mode Fedora installation

Problems During Installation (continued)

Linux+ Guide to Linux Certification, 3e 33

Figure 6-10: The Fedora welcome screen during a text mode installation

Problems During Installation (continued) Installation freezes

Disable Plug-and-Play support in BIOS prior to installation

Installation ends abnormally “fatal signal 11” error displayed

○ Could be problem with RAM○ Often fixed by turning off CPU cache memory

or increasing number of wait states in the BIOS

○ Could also be RAM or CPU voltage issue

Linux+ Guide to Linux Certification, 3e 34

Problems During Installation (continued) Other failure causes include an AMD K6

processor, laptop power management conflicts, overclocked CPUs

Overclocked: running a processor at a higher speed than it is rated forMay lead to increased performanceProduces more heat on processor

○ May result in computer crashes Installation may fail to place boot loader

properlyEnsure that / partition starts before 1024th

cylinder

Linux+ Guide to Linux Certification, 3e 35

Problems After Installation May have problems if installation

program did not detect computer hardware properly or certain programs were not installed

Installation log file: records actions that occur or fail during installation/root/install.log: Lists packages installed or

not installed/root/install.log.syslog: Lists all system

events that occurred during installation

Linux+ Guide to Linux Certification, 3e 36

Problems After Installation (continued) To verify hardware settings, examine

contents of /proc directory or boot-up log filesFor CPU information, view /proc/cpuinfoFor RAM information, view /proc/meminfoFor list of modules, view /proc/modules

To view hardware detected at boot time, use dmesg command

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Problems After Installation (continued)

Linux+ Guide to Linux Certification, 3e 38

Table 6-2: Files commonly found in the /proc directory

Problems After Installation (continued)

Linux+ Guide to Linux Certification, 3e 39

Table 6-2 (continued): Files commonly found in the /proc directory

System Rescue System Rescue: A small bootable Linux

kernel and virtual filesystem used to fix problemsUsed to fix:

○ The boot loader○ Filesystems and partitions○ The configuration file○ Drivers

Can select Rescue installed system at Fedora installation welcome screenMany options regarding how to rescue

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System Rescue (continued)

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Figure 6-11: Selecting System Rescue mount options

System Rescue (continued)

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Figure 6-12: Selecting System Rescue options

System Rescue (continued)

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Figure 6-13: Using the System Rescue BASH shell

Summary

Parallel SCSI HDDs are uniquely identified by a SCSI ID and attach to a controller via a terminated cable

SAS SCSI HDDs transfer information to hard disks using a serial cable

iSCSI is a SAN technology used to transfer information from iSCSI initiators to iSCSI targets across a network

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Summary (continued) RAID is used in Linux servers to

combine several hard disks into one for speed or fault tolerance

RAID can be implemented by software, hardware, or the system BIOS

Different levels of RAID determine how disks are combined and written to

Linux can be installed using files located on CD, USB flash drive, hard disk, and NFS, FTP, and HTTP servers

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Summary (continued) Use a kickstart file to simplify the

installation of Linux on several computers Unsupported video cards, overclocked

CPUs, PnP support, and improper RAM settings can cause an installation to fail

The /proc directory contains information regarding detected hardware and is useful when verifying whether an installation was successful

You can use the System Rescue feature to access and repair a damaged Linux installation

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