Chapter 10: Standard Operating and Maintenance Procedures

1
Chapter 10 Standard Operating and Maintenance
Procedures

• A Guide to Operating Systems Troubleshooting
  and Problem Solving

2
Chapter Objectives

• Explain file system maintenance techniques for
  different operating systems
• Perform regular file system maintenance by
  finding and deleting unused files and directories
• Perform disk maintenance that includes
  defragmenting, relocating files and folders,
  running disk and file repair utilities, and
  selecting RAID options
• Set up and perform disk, directory, and file
  backups
• Explain how to install software for best
  performance
• Tune operating systems for optimal performance

3
File System Maintenance

• Some basic rules for creating a file structure
  include
• Keep the number of directories in the root
  directory to a minimum
• Keep operating system files in the default
  directories recommended by the vendor
• Keep different versions of software in their own
  directories
• Keep data files in directories based on the
  function of those data files
• Design home directories to match the functions of
  users in an organization

4
Applications Directories and Subdirectories
5
UNIX Directories

• \bin houses system files
• \dev contains device files
• \etc holds configuration files
• \home holds user home directories
• \mnt is used for mounting removable drives such
  as CD-ROM drives
• \sbin contains system files
• \mp holds temporary files
• \usr contains programs
• \var holds files that change frequently

6
Typical UNIX Root Directory Structure
7
Windows 98 Operating System Files in the Windows
Folder
8
Operating System Directories
9
Windows-Based Application Software Components
10
Finding and Deleting Files

• A well-organized file structure on the computer
  makes it easier to find and delete unneeded files
• Hard disk drives should be kept to under 80 full
• Drives that are over 80 full are subject to
  excessive wear and are more likely to have
  problems or fail

11
Finding and Deleting Files in Mac OS

• Make sure that you do not run out of disk space
• The Mac OS provides an easy way to assess
  available disk space by simply checking the
  header information in the HD window to display
  the contents of any folder
• The header provides information about the number
  of items and the available disk space in MB
• Use the Sherlock utility for complex search
  criteria
• Files are not truly deleted until they are purged
  by emptying the trash

12
Finding and Deleting Files in NetWare

• There are several ways to manage files
• NetWare Administrator
• NetWare clients
• Network Neighborhood
• NDIR runs from a NetWare DOS and provides
  important information about directory space
• When you create a home directory for a user, make
  sure you restrict the size of the directory by
  using NetWare Administrator

13
NetWare File System Commands

• /AC BEF to view files that have not been accessed
  since the date specified
• /DATE to view information based on the date
• /DO to view all information on directories
• /OW to view files by owner
• /REV SORT SI to sort files listing the largest
  first
• /SPA to view how directory space is used
• /SORT OW to sort files on the basis of ownership
• /VOL to view information by volume

14
UNIX File System Commands

• Use the ls command to view UNIX files.
• Options associated with this command
• a lists all files
• d presents file information on the basis of the
  specified argument
• F identifies the directory contents on the basis
  of directory, executable files, and symbolic
  links (since UNIX is case sensitive, this option
  should be capitalized while the others are not)\
• I displays the inode number for each file

15
UNIX File System Commands (Continued)

• l presents a detailed information listing
  including permissions and file size
• n displays UIDs and GIDs of those who have access
  to files
• r sorts files in reverse alphabetic order
• s displays files on the basis of the data when
  they were last modified
• u displays files on the basis of the time when
  they were last modified
• Files and folders are deleted in UNIX by using
  the remove (rm) command
• Two options can be added to the command -i and
  -r

16
Finding Files in UNIX

• Files can be found on the basis of the filename.
  
• A wildcard character () can be associated with
  part of the name, the size of the file, and the
  last time it was accessed or modified
• Commands used with find
• atime for last accessed time
• ctime for last changed time
• mtime for last modification time
• name for the file name, including the use of
  wildcard searches
• print to print the results of the find
• size for file size (in blocks or in bytes
  (specified by c after value)

17
More UNIX File System Finding Commands

• UNIX provides commands to help you assess the
  allocation of disk space
• df enables you to view information on the basis
  of the file system It provides statistics on the
  total number of blocks, number used, available
  and the percent of capacity used
• du displays statistics for a given directory or
  subdirectory
• On a UNIX computer that acts as a server, the
  administrator has the option to set up disk
  quotas called edquota command

18
UNIX Disk Quotas for Server Users
19
Finding and Deleting Files in DOS, Windows
3.1/3.11

• Many Windows-based programs create temporary
  files
• These files are created as work files or backup
  files for programs such as word processors,
  spreadsheets, databases, queries, and backups
• The files are often located in the following
  places
• A temporary directory in the root, such as
  c\temp
• A temporary directory in the Windows directory,
  such as c\Windows\temp
• A DOS directory in the root, for Windows 3.1,
  3.11 and Windows 95
• A data directory in which word processing,
  spreadsheet, or database files are stored

20
Finding and Deleting Files in DOS, Windows
3.1/3.11 (Continued)

• The applications directory that contains the
  executable file which created the temporary file
• Any temporary directory specified by an
  environment variable in the AUTOEXEC.BAT file,
  such as by the command SET TEMPC\Windows\temp
• Temporary files in DOS and Windows-based systems
  frequently are indicated by a tilde () at the
  beginning of the files
• Use the DIR command in DOS to locate temporary
  files to delete
• In Windows 3.1/3.11, you can use the File Manager
  utility to locate temporary files

21
Windows 3.x File Manager Search Dialog Box
22
Windows 3.x Search Results
23
Finding and Deleting Files in Windows 95/ 98 and
Windows NT

• Temporary files often begin with a tilde () as a
  first character or have a .tmp extension
• In Windows NT the operating system is located in
  the \Winnt folder
• temporary files are found in this folder and in
  the \Winnt\System32 and \Winnt\Temp folders
• Before searching for temporary files, make sure
  to close all active applications so that there
  are no open temporary files

24
Finding and Deleting Files in Windows 95/98 and
Windows NT (Continued)

• Windows 95/ 98 and Windows NT retain deleted
  files in the Recycle Bin by default
• There is an option to turn off retention of
  deleted files or to periodically empty the
  Recycle Bin
• By default, the Recycle Bin can grow to occupy
  10 of the available hard disk storage

25
Windows NT 4.0 Find Dialog Box
26
Temporary Files Found in Windows NT 4.0
27
Maintaining Large and Small System Disks

• Maintain the integrity of files and ensure disk
  performance using the following techniques
• Defragment disks
• Move files to spread the load between multiple
  disks
• Use disk utilities to repair damaged files
• Deploy RAID techniques that extend the life of
  disks and provide disk redundancy

28
Defragmenting Disks

• Fragmentation - unused space develops between
  files
• As the operating system deletes files, creates
  new files, and modifies files, the unused space
  between them grows and becomes scattered
  throughout the disk
• The disk read-write head begins to move over more
  disk area to find individual files
• disk performance suffers
• the read-write head works harder

29
More About Defragmenting

• In mainframes and minicomputers that have large
  hard disks, fragmentation is sometimes obvious
  because the constant activity of the read-write
  head causes the disk drive cabinet to literally
  move across the floor
• In small disk drives, the problem is apparent
  through excessive noise and hard disk activity
• Defragmentation is the process of removing the
  empty pockets between files and other information
  on the hard disk drive

30
Files Located Contiguously on a Disk
31
A Fragmented Disk
32
Defragmenting Disks (Continued)

• There are two ways to defragment
• Take a complete backup of a disks contents and
  then perform a full restore
• Run a disk defragmentation tool
• Surface analysis tools are destructive to data
• DOS, Windows 3.1/ 3.11, Windows 95/ 98 have
  built-in defragmentation utilities

33
Disk Defragmenter in Windows 98
34
Defragmenting in Windows NT 4.0

• Windows NT 4.0 does not come with a defragmenting
  tool, but third-party software companies offer
  them
• Windows NT server has frequent write and update
  activity. It may need to be defragmented every
  month

35
Defragmenting in UNIX

• Some versions of UNIX come with defragmenting
  tools, such as defragfs
• They may not rearrange files
• Compunix, DEC, Eagle Software, and other
  companies offer full-feature UNIX disk
  defragmentation tools

36
Defragmenting in Mac OS

• The Mac OS is designed to minimize disk
  fragmentation, but third-party tools are
  available for systems that experience high use
• SYMANTECs Norton Utilities for Macintosh
  includes a Mac OS version of SpeedDisk for
  defragmenting
• memory fragmentation is more likely to need
  attention in the Mac OS

37
Moving Disk Files to Spread the Load

• Spread files evenly across disks when there is
  more than one disk to help extend the life of
  disk drives
• This technique is used mainly on computers that
  have multiple user access, such as servers, and
  on which there is frequent disk activity
• Files have to be moved on the basis of their
  function

38
Mac OS Disk Utilities for Repair

• Disk First Aid is a Mac OS utility verifies
  files, folders and mounted disks
• Before verifying a disk, it is necessary to turn
  file sharing off

39
UNIX Disk Utilities for Repair

• Fsck utility is used to check one or more file
  systems
• P-fsck utility checks two or more file systems
  simultaneously, instead of one at a time
• P-fsck should not be applied to the root file
  system

40
Chkdsk Disk Utility

• Runs in DOS or at the command prompt in Windows
  NT
• The Windows NT version of the utility is more
  powerful
• It incorporates some of the features of ScanDisk
  (Windows NT does not have a ScanDisk utility)
• There are two options or switches that can be
  used with chkdsk
• /f switch instructs chkdsk to repair errors
  without a yes or no interactive query
• /v switch causes chkdsk to display all files as
  it checks them

41
Chkdsk in DOS
42
Chkdsk Find and Fix

• For versions of Windows other than Windows 98,
  chkdsk can find and fix the following problems
• Damage to the root directory or to another
  directory
• Problems with the directory structure that causes
  chkdsk to be unable to process a full tree
• Disk space that is not allocated
• Files that share the same allocation units
• A file pointer to an allocation unit that does
  not exist
• Files that are assigned more allocation units
  than they need

43
Chkdsk Find and Fix

• Directories that have no entries
• Damaged directories that cannot be repaired
• A full root directory ( the limit is 512 files)
• Disk sectors that cannot be read
• Damaged subdirectory entries, such as damaged
  pointers to parent directories
• File Allocation Table entry problems or a damaged
  File Allocation Table
• Allocation units that contain partial information
  but that have no links to files
• Bad file attributes

44
Examples of .chk Files
45
Switches for Windows NT Chkdsk

• /r switch instructs chkdsk to look for bad
  sectors and attempt to relocate information that
  it is able to read
• /lsize switch is used to change the size of the
  log file in NTFS
• chkdsk is run automatically only in Windows NT

46
ScanDisk for DOS, Windows 3.1/3.11 and Windows
95/98

• ScanDisk is a disk verification utility that runs
  from DOS
• enter SCANDISK at the command prompt
• ScanDisk initially checks the media descriptor,
  file allocation tables, directory structure, and
  file system on a hard drive the creates a log of
  the results
• In Windows 95/ 98, ScanDisk is a Windows-based
  application

47
Windows 3.1 ScanDisk
48
ScanDisk Advanced Options

• How to display the summary information
• How to handle cross-linked files
• How to handle lost file fragments
• How to verify files
• Whether or not to report DOS name length errors

49
Deploying RAID Techniques

• RAID is used to extend the life of a set of disks
• RAID does this through disk striping, a technique
  for spreading data over multiple disk volumes
• There are two general ways to deploy RAID
• Hardware RAID
• Software RAID

50
RAID Levels

• RAID level 0 provides disk striping and requires
  the use of two or more disks
• RAID level 1 uses two disks that are mirror
  images and does not use disk striping
• RAID level 2 provides disk striping and all disks
  contain information to help recover data
• RAID level 3 is identical to RAID level 2, but
  error recovery information is contained on one
  disk
• RAID level 4 provides disk striping and adds
  checksum verification information that is stored
  on one disk
• RAID level 5 is the same as RAID level 4, except
  that checksum verification is stored on all
  disks. It can rebuild a failed drive without
  shutting down the server

51
Making Backups

• Binary backup - backs up the disk contents in
  binary format
• Full file-by-file backup - backs up the disk
  contents as individual directories and files
• Differential backup - backs up all files that
  have an archive attribute
• Incremental backup - backs up all files that have
  the archive attribute, then removes the attribute
  from each file
• requires less tapes than differential backup

52
Backups in UNIX

• UNIX uses two utilities for backing up files
• Volcopy - a binary backup that creates a mirror
  image of a disk. It requires specifics about the
  length and density of the information to be
  backed up
• Dump utility - used for full or partial
  file-by-file backups. It backs up all files,
  changed files, or files changed after previous
  backup
• Tar utility - designed for archiving tapes and
  includes file information as well as the archived
  files

53
Backups in NetWare

• NetWare uses its Storage Management System (SMS)
  for creating backups
• Three NetWare Loadable Modules (NLMs) are loaded
  at the server console
• target server software (TSA410)
• target NDS agent (TSANDS to back up the NDS
  database)
• backup device drivers (SBACKUP)

54
Backups in Windows NT

• Windows NT Server and Workstation have Backup
  utility options
• Normal backup (full file-by-file backup)
• Incremental backup
• Differential backup
• Daily backup for files that have changed on the
  same day as the backup
• Copy backup that is performed only on specified
  files
• Prior to backup
• backup media must be installed
• backup media driver must be installed

55
Windows NT 4.0 Backup
56
Backups in Windows 95/ 98

• Backups are created as jobs that are given titles
  
• The Backup utility displays all drives recognized
  by Windows 95/ 98, including mapped drives

57
Backups in DOS and Windows 3.1/3.11

• DOS, Windows 3.1/ 3.11 all use the same DOS based
  utility called BACKUP
• Backed up files are restored via the RESTORE
  command
• The BACKUP utility copies the specified files to
  floppy disks, creating two files per disk
• BACKUP.xxx
• CONTROL.xxx

58
BACKUP Command Switches

• /a - Adds files to a backup disk that already
  contains backup files
• /d - Backs up files that are new or changed, on
  or after the specified data
• /f - Formats the disk prior to backing up files
• /l - Causes a log file to be created with the
  name entered after the /l command, such as
  /lbacklog
• /m- Only backs up files that have the archive
  attribute
• /s - Backs up subdirectories and their contents
• /t - Backs up the files created or changed on or
  after the specified time

59
Checklist of Guidelines for Software Installation

• Make sure the software is compatible with the
  operating system
• Make sure hardware is compatible with the
  software
• Find out if there are different installation
  options
• For Microsoft operating systems, determine if the
  software is DOS-based or Windows-based and if any
  special drivers are required
• Windows NT may not run some DOS-based software,
  games, and 160-bit Windows-based software

60
Checklist of Guidelines for Software Installation
(Continued)

• Check to see if there are programs that attempt
  to directly manage hardware and peripherals
  these may not be allowed to function in Windows
  NT because they go through the system kernel
• Use any utilities provided by the operating
  system for installing software
• Look in the documentation or ask the vendor for
  software that is written to take advantage of the
  Registry for Windows 95/ 98 and Windows NT
  applications

61
Checklist of Guidelines for Software Installation
(Continued)

• Check the vendors bug list for software to
  make sure there are no bugs
• Make sure that the software is well documented
  and supported and drivers are provided
• Determine in advance how to backup important
  files associated with the software and find out
  the locations and purposes of all hidden files
• Determine if running the program requires
  adjustments to page or swap files used by the
  operating system

62
Checklist of Guidelines for Software Installation
(Continued)

• Find out what temporary files are created by the
  program
• Always install the latest versions of Windowss
  components, including .DLL, .OCX, .INI, .INF, and
  .DRV files
• Do not mix .INF and driver files between
  different versions of Windows
• Always keep service patches up to date for all
  software. Service Packs are issued by the vendor
  to fix software problems, address compatibility
  issues, and to add enhancements

63
Installing Software on a Network Requirements

• Make sure there are enough licenses to match the
  number of users or that metering software is in
  place that limits simultaneous use
• Determine if the software is network compatible
• Determine the network load created by the
  software
• Consider purchasing management software that can
  automatically update system-wide software when
  there is a new release

64
Installing Software on a Network Requirements
(Continued)

• Determine if the software will be loaded from the
  server or permanently installed at the
  workstations
• Determine if the server or workstations must be
  tuned for the software
• For operating systems that support two or more
  file systems, make sure that the software is
  compatible with the file system that is in use

65
Tuning the Operating System

• Workstations and server operating systems need
  periodic tuning
• slow workstations and servers have a cumulative
  impact on a network

66
Tuning Virtual Memory

• Virtual memory is disk storage that is used when
  there is not enough RAM for all processes
• When the operating system and CPU need to access
  the information on disk, they swap something else
  to disk, using a process called paging
• The information swapped back and forth from RAM
  to disk and vice versa is stored in specially
  allocated disk area called the paging or swap
  file
• Some operating systems enable a user to tune the
  paging file by adjusting its size
• Windows 3.1/ 3.11, Windows 95/ 98 all make use
  of paging

67
Tuning Virtual Memory (Continued)

• In UNIX, use the vinstat utility along with the
  --s option to monitor paging
• iostat can also be used to track disk activity
• Virtual memory in Windows NT is adjusted to set
  an initial starting size and a maximum size
• Set the initial size to equal the amount of RAM
  plus 12 MB
• Monitor RAM and page file activity through the
  Task Managers Performance tab
• a page file can be created on each physical hard
  disk

68
Tuning Virtual Memory (Continued)

• It is a good idea to create multiple page files
  with these exceptions
• avoid creating a page file on the disk that
  contains the system files
• do not create a page file on a RAID set of disks
  when using software RAID levels 0 or 5
• do not create a page file on the backup volume in
  a mirrored set

69
Tuning for Network Communications

• Networks should be checked periodically to make
  sure that the connectivity is optimized
• Inspect the cable and connector into the computer
  for damage
• Operating systems need periodic patches. So do
  NIC drivers.
• Periodically check which protocols are configured
  and to eliminate those which are no longer used
• Windows NT enables users to specify the order
  used to handle protocols on a multi-protocol
  network
• set the protocol order so that the most
  frequently used protocol is handled first

70
Windows NT Network Access Order
71
Chapter Summary

• Maintaining an operating system is as important
  as setting it up
• One important technique for maintaining an
  operating system is to regularly find and delete
  unused files
• Designing a well-organized file structure is a
  vital part of this maintenance technique

72
Chapter Summary

• Disk scan and repair tools are an inexpensive way
  to fix disk problems
• Other maintenance techniques include disk
  defragmentation, moving files to relatively
  unused disks, and installing RAID
• RAID techniques are frequently used to add longer
  disk life as well as protect data

73
Chapter Summary

• Make sure software is compatible with the
  computer hardware and operating system
• Use software installation tools and features
  built into the operating system
• All operating systems should be tuned
  periodically by adjusting paging and installing
  current system patches and updates