Chapter 6 Advanced 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 2

Objectives (continued)  Install Fedora Linux using a kickstart file  Troubleshoot the installation process  Access an installed system using System Rescue 3

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 4

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 5

Parallel SCSI Configuration (continued) 6 Figure 6-1: Connecting parallel SCSI devices

Parallel SCSI Configuration (continued) 7 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 8

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 9

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 10

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 11

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 12

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 13

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 14

RAID Configuration (continued) 15 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 CDs USB flash memory drive ISO image on local hard disk ISO image through network server 16

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 17

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 18

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 19

Hard Disk Installation (continued) 20 Figure 6-3: Selecting a nonstandard installation method

Hard Disk Installation (continued) 21 Figure 6-4: Selecting the installation media location

Hard Disk Installation (continued) 22 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 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 23

Network-Based Installations (continued) 24 Figure 6-6: Specifying the location of the Fedora ISO image on an NFS server

Network-Based Installations (continued) 25 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 script Specifies normal OS installation choices ks.cfg Contains sections on system configuration, disk partitioning, and package selection 26

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 27

Automating Linux Installations (continued) 28 Figure 6-8: The Kickstart Configurator

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 29

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 30

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 31

Problems During Installation (continued) Linux+ Guide to Linux Certification, 3e32 Figure 6-9: Starting a text mode Fedora installation

Problems During Installation (continued) Linux+ Guide to Linux Certification, 3e33 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, 3e34

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 1024 th cylinder Linux+ Guide to Linux Certification, 3e35

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, 3e36

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 Linux+ Guide to Linux Certification, 3e37

Problems After Installation (continued) Linux+ Guide to Linux Certification, 3e38 Table 6-2: Files commonly found in the /proc directory

Problems After Installation (continued) Linux+ Guide to Linux Certification, 3e39 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 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 40

System Rescue (continued) 41 Figure 6-11: Selecting System Rescue mount options

System Rescue (continued) 42 Figure 6-12: Selecting System Rescue options

System Rescue (continued) 43 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 44

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 45

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 46