Linux Guide to Linux Certification, Third Edition

1
Linux Guide to Linux Certification, Third Edition

• Chapter 6
• Advanced Installation

2
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

3
Objectives (continued)

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

4
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 SCSI
• Serial Attached SCSI
• iSCSI

5
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 controller
• Target ID
• Identifies priority

6
Parallel SCSI Configuration (continued)
Figure 6-1 Connecting parallel SCSI devices
7
Parallel SCSI Configuration (continued)
Table 6-1 Common SCSI standards
8
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

9
Serial Attached SCSI Configuration

• Serial attached hard disks connected to SCSI
  controller via serial cables with small serial
  connectors
• More than 60,000 devices per controller
• Configuration steps
• Connect hard disk to controller via correct
  serial cable
• Ensure that hard disk is detected by system or
  SCSI BIOS
• The rest is performed automatically by controller

10
iSCSI Configuration

• Internet SCSI (iSCSI) uses network cables to
  transfer data to/from remote hard disks
• iSCSI 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 manufacturer
• Must specify configuration settings during the
  Linux installation

11
RAID Configuration

• Fault tolerant device exhibiting minimum
  downtime after failure
• Redundant Array of Inexpensive Disks (RAID)
• Typical implementation of fault tolerant disk
• Can be used to speed up access to hard disk
• Combines several HDDs storage space
• Seven RAID configurations
• Hardware-, software-, or firmware-based
• Different configuration process for each type

12
RAID Configuration (continued)

• Spanning two HDDs seen as one volume
• RAID level 0, not fault tolerant
• Good when need large amount of space in single
  volume
• Disk striping write a portion of the information
  to each of multiple HDDs
• RAID level 0 not fault tolerant
• Decreases read/write time
• Disk mirroring two identical hard disks
• RAID level 1 fault tolerant

13
RAID Configuration (continued)

• RAID level 2 no longer used
• Disk striping with parity write portions
  information to different HDDs and maintain parity
  information
• RAID 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 minimum
• If any of the HDDs fail, the information can be
  recovered from the other HDDs
• RAID 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)
Figure 6-6 Organization of data on RAID level 5
16
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 CDs
• USB flash memory drive
• ISO image on local hard disk
• ISO image through network server

17
CD Installation

• Requires six CDs
• First CD contains the installation program
• Boot the computer using the first CD, then make
  appropriate choices within the installation
  program
• Will be prompted to insert remaining CDs when
  necessary

18
USB Flash Drive Installation

• BIOS can boot the computer from a flash memory
  drive
• Need to download Linux onto the flash memory
  drive
• Overwrites the existing filesystem on the drive
• From Windows, can use free utilities
• e.g., LiveUSB Creator
• From another Linux computer, use dd command

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Hard Disk Installation

• May install Linux directly from ISO images on
  hard disk
• Must 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

20
Hard Disk Installation (continued)

Figure 6-3 Selecting a nonstandard installation
method
21
Hard Disk Installation (continued)
Figure 6-4 Selecting the installation media
location
22
Hard Disk Installation (continued)

Figure 6-5 Specifying the location of the Fedora
ISO image on the hard disk
23
Network-Based Installations

• Requires installation startup DVD, CD-ROM or
  bootable USB flash memory drive
• Contains NIC drivers and programs allowing
  connection to server
• Select 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

24
Network-Based Installations (continued)
Figure 6-6 Specifying the location of the Fedora
ISO image on an NFS server
25
Network-Based Installations (continued)
Figure 6-6 Specifying the location of the Fedora
ISO image on an HTTP server
26
Automating Linux Installations

• Deploy several Linux servers and workstations
  requiring same configuration
• Kickstart file automated installation script
• Specifies normal OS installation choices
• ks.cfg
• Contains sections on system configuration, disk
  partitioning, and package selection

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Automating Linux Installations (continued)

• Kickstart configuration configure a new
  kickstart file
• Use Kickstart Configurator tool
• To use ks.cfg
• Place ks.cfg on CD, DVD, floppy disk, or hard
  disk partition
• Boot from installation startup DVD
• At 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)
Figure 6-8 The Kickstart Configurator
29
Troubleshooting Installation

• Computers typically have different BIOS
  configurations
• Installing on different computers is rarely the
  same
• Problems primarily related to hardware support or
  configuration
• Typically fixed by changing hardware configuration

30
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

31
Problems During Installation

• For graphical installation, video card and mouse
  must be detected
• Appropriate drivers must be loaded
• Video 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

32
Problems During Installation (continued)

Figure 6-9 Starting a text mode Fedora
installation
33
Problems During Installation (continued)

Figure 6-10 The Fedora welcome screen during a
text mode installation
34
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

35
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 for
• May lead to increased performance
• Produces more heat on processor
• May result in computer crashes
• Installation may fail to place boot loader
  properly
• Ensure that / partition starts before 1024th
  cylinder

36
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

37
Problems After Installation (continued)

• To verify hardware settings, examine contents of
  /proc directory or boot-up log files
• For CPU information, view /proc/cpuinfo
• For RAM information, view /proc/meminfo
• For list of modules, view /proc/modules
• To view hardware detected at boot time, use dmesg
  command

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Problems After Installation (continued)
Table 6-2 Files commonly found in the /proc
directory
39
Problems After Installation (continued)
Table 6-2 (continued) Files commonly found in
the /proc directory
40
System Rescue

• System Rescue A small bootable Linux kernel and
  virtual filesystem used to fix problems
• Used to fix
• The boot loader
• Filesystems and partitions
• The configuration file
• Drivers
• Can select Rescue installed system at Fedora
  installation welcome screen
• Many options regarding how to rescue

41
System Rescue (continued)
Figure 6-11 Selecting System Rescue mount
options
42
System Rescue (continued)
Figure 6-12 Selecting System Rescue options
43
System Rescue (continued)
Figure 6-13 Using the System Rescue BASH shell
44
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

45
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

46
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