Operating Systems Management and Maintenance

Objectives
After completing this chapter, you will be able to:
• Explain file system maintenance techniques for different operating
systems
• Perform regular file system maintenance by finding and deleting
unused files and folders
• Perform disk maintenance that includes defragmenting, relocating
files and folders, running disk and file repair utilities, and selecting
RAID options
Guide to Operating Systems, 5th Edition 4
Objectives
After completing this chapter, you will be able to (cont’d):
• Explain the types of backups and develop a backup plan
• Explain how to install software for best performance
• Tune operating systems for optimal performance
Guide to Operating Systems, 5th Edition 5
File System Maintenance
• A well-planned file structure makes it easy to locate files, update files, share
folders and files, back up and archive files, and delete unwanted files
• Basic rules for creating a file structure:
• Keep a manageable number of folders in the root folder
• Keep OS files in the default folders
• Keep different versions of software in their own folders
• Keep data files in folders on the basis of their functions
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File System Maintenance
• Basic rules for creating a file structure (cont’d):
• Design home folders to match the functions of users
• Group files with similar security needs within the same
folders
• OS folders are typically placed in the root folder
Guide to Operating Systems, 5th Edition 7
Table 11-1 Essential operating system folders
File System Maintenance
• Advantages to installing and leaving OS files in default folders:
• Easier for others to help with computer problems
• Many software installations expect OS files to be in the default locations
• In Windows, installed software is tracked in the registry
• Easier for the OS to assist when software must be uninstalled for upgraded
because the OS can quickly identify and find relevant components
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File System Maintenance
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Table 11-2 Examples of Windows-based application software components
File System Maintenance
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Table 11-3 Examples of UNIX/Linux and Mac OS X application software components
File System Maintenance
• If different versions of software are still used:
• Put different versions in different subfolders under a main applications folder
• Example: in Windows Server you can support different version of Microsoft
Word by having a Program Files folder and subfolders called Word2013 and
Word2016
• Also, Microsoft 64-bit OSs offer the Program Files and Program Files (x86)
folders to separate 64-bit and 32-bit applications
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Finding and Deleting Files
• A solid file structure makes it easier to find and delete unneeded files
• Example: temporary files are often created when running some applications
and are sometimes not deleted automatically
• Temporary Internet files (cookies) are often not deleted automatically
• It is good practice to implement a regular schedule for finding and
deleting unneeded files
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Deleting Temporary Files in Windows
• In Windows, temporary files are typically located in
the /Temp and /Windows/Temp folders
• Or in users’ home folders
• Use the Disk Cleanup tool to delete unneeded files
• In Windows 8 and later versions
• The Disk Cleanup tool is scheduled to automatically run
on the system drive where Windows is installed
• You should also regularly open the Recycle Bin and
delete its files
• You can also delete these files using the Disk Cleanup tool
Guide to Operating Systems, 5th Edition 13
Deleting Temporary Files in Windows
Guide to Operating Systems, 5th Edition 14
Figure 11-1 The Disk Cleanup tool in Windows
Deleting Files in UNIX/Linux
• View UNIX/Linux files by using the ls command
• Some of the options that can be used with this command:
• -a lists all files including hidden files
• -C formats the listing in columns for easier reading
• -d lists folders
• -f displays files in an unsorted list
• -l presents detailed information including permissions and file size
• -r sorts files in reverse alphabetical order
• -s displays the size of files (in blocks)
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Deleting Files in UNIX/Linux
• View UNIX/Linux files by using the ls command
• Some of the options that can be used with this command (cont’d):
• -S sorts files and folders on the basis of size
• -t sorts files and folders on the basis of time they were last modified
• Example: ls –a lists all files including hidden files
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Deleting Files in UNIX/Linux
• Files and folders are deleted using the rm command
• Options for this command:
• -i for interactive option (asks if you are sure you want to delete)
• -r for recursive (deletes an entire folder’s contents)
• Example: rm /home/mjackson/docs *.txt
• This command will delete all files with a .txt extension in the
mjackson directory
• In the Linux GNOME File tool, you delete a file by
finding the file, clicking on it and pressing the delete
key on your keyboard
Guide to Operating Systems, 5th Edition 17
Deleting Files in UNIX/Linux
• A file can be found by using the find command
• Options that can be used with this command:
• -atime for last access time
• -ctime for last changed time
• -mtime for last modification time
• -name for the filename, including the use of wildcard searches
• -print to print the results of the find
• -size for file size (in blocks or bytes; with bytes specified by a “c”)
• -user to find files by ownership
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Deleting Files in UNIX/Linux
• Example: if you are looking for a file called file1 in
order to delete it from your home folder, use:
• find ~ -name file1
• Another example: to find a all files in directory/usr
that are owned by the user lpadron:
• find /usr –user lpadron
• Linux GNOME file tool offers a trash can for deleting
files permanently
• Periodically view the contents of Trash and purge them by
clicking Trash in Files and click Empty
Guide to Operating Systems, 5th Edition 19
Deleting Files in UNIX/Linux
• UNIX/Linux provides commands to help you assess
the allocation of disk space:
• df – enables you to view information on the basis of the file
system
• du – used to display statistics for a given directory and its
subdirectories
Guide to Operating Systems, 5th Edition 20
Deleting Files in UNIX/Linux
Guide to Operating Systems, 5th Edition 21
Table 11-4 UNIX/Linux commands for finding and removing files
Deleting Files in UNIX/Linux
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Table 11-4 UNIX/Linux commands for finding and removing files (continued)
Deleting Files in Mac OS X
• Mac OS X is generally effective in automatically cleaning out
temporary files
• However, still important to periodically find and delete unneeded files
• Mac OS X windows often have a list option that shows files and their
sizes
• Click the List view button in the window to see file sizes
Guide to Operating Systems, 5th Edition 23
Deleting Files in Mac OS X
Guide to Operating Systems, 5th Edition 24
Figure 11-2 Viewing file sizes in Mac OS X
Maintaining Disks
• It is important to perform disk maintenance in order to maintain the
integrity of files and ensure disk performance
• Important disk maintenance tasks include:
• Defragmenting disks
• Moving files to spread the load between multiple disks
• Using disk utilities to find and repair damaged files
• Deploying RAID techniques that extend the life of disks and provide disk
redundancy
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Defragmenting Disks
• Fragmentation – unused space develops between files and other
information written on a disk
• When an OS is first installed, files are placed contiguously on a disk
(little or no unused space between files)
• As the OS deletes files, creates new files, and modifies files, the
unused space between them grows and becomes scattered
• The greater the fragmentation, the more space is wasted
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Defragmenting Disks
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Figure 11-3 An unfragmented disk
Defragmenting Disks
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Figure 11-4 An fragmented disk
Defragmenting Disks
• Defragmentation – process of removing empty pockets between files
and other information on a hard drive
• Ways to defragment:
• Older method is to take a complete backup of a disk’s contents and perform a
full restore
• Some administrators run a surface analysis of a disk before the restore to find damaged
disk sectors and tracks
Guide to Operating Systems, 5th Edition 29
Defragmenting Disks
• Ways to defragment (cont’d):
• Another option is to run a disk defragmentation tool
• Many OSs come with a built-in tool to defragment disks
• Some can run in the background as you use your computer
• Some perform a quick analysis to see if defrag is even needed
• If disk fragmentation is 20% or less, the disk does not need to be defragmented immediately
Guide to Operating Systems, 5th Edition 30
Defragmenting Disks
• In UNIX/Linux and Mac OS X, file systems are designed to reduce the
need for defragmenting
• OSs first write to a hidden journal, which is loaded to memory and then
contents are written to disk in a linear fashion
• Linear – data is temporarily stored and written all at one time in more contiguous fashion
• Sequential – data is not stored but written as soon as it is created and therefore written
to whatever disk areas are immediately open
• Defragmentation tools are usually not included with these OSs
Guide to Operating Systems, 5th Edition 31
Moving Disk Files to Spread the Load
• A technique that can help extend the life of disk drives is to spread
files evenly across disks
• Usually used in servers
• Before files are moved, administrators examine disk and file activity to
determine how to spread files to achieve even loading
• Disk activity is monitored in Windows using Task Manager, Resource Monitor,
and Performance Monitor
• For a quick look at current disk utilization, use Resource Monitor
Guide to Operating Systems, 5th Edition 32
Moving Disk Files to Spread the Load
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Figure 11-5 Using Resource Monitor to view disk usage
Using Disk Utilities to Repair Damaged Files
• The following utilities enable you to repair damaged files and file
links:
• Disk First Aid in the Mac OS X Disk Utility
• fsck and p_fsck in UNIX/Linux
• chkdsk in Windows
Guide to Operating Systems, 5th Edition 34
Deploying RAID Techniques
• RAID – used by server operating systems for three purposes:
• Increased reliability (providing data recovery when a disk drive fails and
extending the useful life of disks)
• Increased storage capacity
• Increased speed
• This section focuses on how RAID is used to extend the life of a set of
disks
• RAID does this using disk striping – technique for spreading data over
multiple disk volumes
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Deploying RAID Techniques
• Earlier, you were introduced to many levels of RAID
• Only those that use disk striping distribute the load across multiple disks:
RAID 0 and RAID 5
• Another RAID level, not discussed earlier, is RAID 10 which provides striping
plus mirroring
• RAID levels 2, 3, and 4 are rarely used because levels 1, 5, and 10 provide
better fault tolerance
• Two ways to deploy RAID: hardware and software
• Software RAID is slower than hardware RAID
Guide to Operating Systems, 5th Edition 36
Making Backups
• Several types of backups:
• Binary backup – backs up the disk contents in binary format to create an exact
image of the disk contents
• Simple to perform and includes everything on the disk
• Disadvantage – cannot restore individual files or directories
• Full file-by-file backup – all of the disk contents are back up, but as individual
directories and files
• Enables you to restore a single directory or a set of files without restoring the entire disk
Guide to Operating Systems, 5th Edition 37
Making Backups
• Several types of backups (cont’d):
• Differential backup – backs up all files that have an archive attribute (indicates
that the file needs to be backed up)
• Incremental backup – backs up all files that have the archive attribute, and
removes the attribute from each file after backup
Guide to Operating Systems, 5th Edition 38
Making Backups
• Basic backup scheme might include:
• Full file-by-file backup to tape each Saturday evening and differential backups
to tape Monday through Friday
• The business might also have four sets of tapes that are rotated each week
• First tape set would be used in week 1
• Second tape set would be used in week 2, and so on
• If one tape set goes bad, there is an option to use one of the tape sets from a previous
week to restore, if needed
Guide to Operating Systems, 5th Edition 39
Making Backups
• Basic backup scheme might include (cont’d):
• If there was a catastrophic disk failure on Thursday:
• The business would restore the full backup from the previous Saturday and restore the
differential backup from Wednesday night
• For small server backups, a simple solution is to use the ability of the
native backup software to periodically back up new files
• Mac OS X Time Machine enables you to leave a removable hard drive
connected to the computer so it can back up any file changes after they occur
Guide to Operating Systems, 5th Edition 40
Making Backups
• When creating a backup strategy:
• Determine what information needs to be backed up and how often
• Use scheduling
• Choose the right backup media
• Rotate backup media
• Store a set of backups in an off-site location
• Regularly use file repair tools and a virus checker
• Investigate third-party backup software
Guide to Operating Systems, 5th Edition 41
Optimizing Software Installation
• Guidelines for software installation:
• Make sure that the software is compatible with your OS
• Check the CPU, RAM, disk storage, audio, video, and other requirements to
make sure you meet minimum requirements
• Find out if there are different installation options
• Use the utilities provided by the OS for installing or uninstalling applications
• In Windows, there is likely to be a Windows-compatible setup program that comes with
the software
Guide to Operating Systems, 5th Edition 42
Optimizing Software Installation
• Guidelines for software installation (cont’d):
• Check the vendor’s “bug” list to make sure there are no bugs that will impact
the way you will use the software
• Make sure the software is well documented and supported by the vendor
• Determine, in advance, how to back up important files associated with the
software
• Determine whether running the program requires adjustments to page or
swap files used by the OS (page/swap files are covered in the next section)
Guide to Operating Systems, 5th Edition 43
Optimizing Software Installation
• Guidelines for software installation (cont’d):
• Find out what temporary files are created by the program
• Always install the latest versions of components (drivers)
• Do not mix .inf and driver files between different versions of Windows
• Always keep service packs and program patches up to date for all software
Guide to Operating Systems, 5th Edition 44
Optimizing Software Installation
• Consider the following when installing network
server software:
• Make sure there are enough licenses to match the
number of users
• Determine the network load created by software
• Consider purchasing management software that can
automatically update system-wide software when there is
a new release
• Determine if the software will be used in a cloud,
client/server, terminal server/remote desktop services
environment or if it will be loaded directly onto server
clients
Guide to Operating Systems, 5th Edition 45
Optimizing Software Installation
• Consider the following when installing network
server software (cont’d):
• Determine whether the server or client workstations must
be tuned for the software in a particular way
• For OSs that support two or more file systems, make sure
that the software is compatible with the file system used
by the OS
Guide to Operating Systems, 5th Edition 46
Tuning the Operating System
• After an OS is installed, periodic tuning is a must
• Slow workstations and servers have a cumulative impact on a network
• Sometimes poor network performance is not a result of network
problems or too little bandwidth
• Could be that workstations and servers cannot keep up with the network
• Many ways to tune OSs:
• Tuning virtual memory
• Installing OS updates and patches
• Tuning for optimal network communications
Guide to Operating Systems, 5th Edition 47
Tuning Virtual Memory
• Virtual memory – disk storage that is used when
there is not enough RAM for a particular operation,
or for all processes currently in use
• OS swaps to disk (VM) the processes and data in RAM that
temporarily have a low priority
• When the OS need to access information on disk, they
swap something else to disk – this process is called paging
• Page file or swap file – specially allocated disk area where
information is swapped back and forth from RAM to disk
• Called swap file system in UNIX/Linux
Guide to Operating Systems, 5th Edition 48
Tuning Virtual Memory
• Virtual memory (in Windows) is adjusted to set an
initial starting size and a maximum size to which it
can grow
• The general rule for sizing the page file is to set the initial
size to equal 1.5 times the amount of RAM
• In Windows 8, Windows Server 2012, and later
versions
• The paging file size is configured by default to be
automatically managed by Windows
Guide to Operating Systems, 5th Edition 49
Tuning Virtual Memory
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Figure 11-7 Configuring the paging file in Windows
Tuning Virtual Memory
• In UNIX/Linux – use the vmstat command-line utility
to monitor paging
• If a swap file system is not already created, you can use
the mkfs command in Linux to create it
• In Mac OS X there is no option for turning on or
configuring virtual memory because it is always
enabled and monitored by the OS
Guide to Operating Systems, 5th Edition 51
Installing Operating System Updates and
Patches
• Installing updates and patches is one of the most important ways to
keep your OS tuned
• You can obtain updates by using the Windows Update utility in all
Windows OSs
• Windows 10 is configured to automatically download and install updates
• Many Linux distributions with GNOME have a software update tool
that allows you to automatically obtain updates
• Mac OS X uses the App Store to deliver updates
Guide to Operating Systems, 5th Edition 52
Installing Operating System Updates and
Patches
Guide to Operating Systems, 5th Edition 53
Figure 11-8 Windows Update
Installing Operating System Updates and
Patches
Guide to Operating Systems, 5th Edition 54
Figure 11-9 Checking for updates on Mac OS X
Tuning for Network Communications
• NIC cards used should be of high quality and designed for use in the
computer’s fastest expansion slot
• You should occasionally check for updated NIC drivers for your
network interface card
• NICs can sometimes saturate the network with repeated packet
broadcasts – called a broadcast storm
• Network traffic should be regularly monitored to make sure no node
is creating excessive traffic
Guide to Operating Systems, 5th Edition 55
Testing Network Connectivity
• ping utility – used to poll another network device
• ping displays statistics that include the number of packets sent,
received, and lost
• Also provides the round trip time in milliseconds
• You can check the utilization of your network connection in Windows
using the Performance tab in Task Manager
• To check utilization of your interface in Linux, you may need to
download and install a utility such as netdiag or netwatch
Guide to Operating Systems, 5th Edition 56
Testing Network Connectivity
Guide to Operating Systems, 5th Edition 57
Figure 11-11 Checking network interface utilization in Windows
Testing Network Connectivity
• On Mac OS X, you can run Activity Monitor and check the Network
tab to see what processes are using network bandwidth
• And to see basic statistics for the number of packets received and sent
Guide to Operating Systems, 5th Edition 58
Summary
• Successful file system maintenance is closely linked to a computer’s
folder structure
• The file structure established on a computer is related to how easy it
is to maintain that computer over the long term
• One important practice for maintaining an OS is to regularly find and
delete unused files
• Use Disk Cleanup tool in Windows, the find, ls, and rm commands in
Linux, and the Find utility in Mac OS X to find and delete unused files
Guide to Operating Systems, 5th Edition 59
Summary
• Other ways to maintain disks include defragmenting disks, moving
files to relatively unused disks, finding and repairing disk problems,
and setting up RAID
• An important part of maintaining a system is to make regular backups
• An important consideration for optimizing software installations is to
make sure the software is compatible with computer hardware and
OS
Guide to Operating Systems, 5th Edition 60
Class Work
• Make a group of 3
• Answer the following topics

  1. Files
  2. Deleting temporary files in Windows
  3. Deleting Files in Linux/UNIX
  4. Defragmentation in Windows
  5. Defragmentation in UNIX/Linux & Mac OS X
  6. Backup
  7. Virtual Memory – Page/Swap file

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