The Importance of Disk Defragmentation
Table of Contents
Introduction
I am sure many of you have been told in the past to defrag your
hard drives when you have noticed a slow down on your computer. You may have
followed the advice and defragged your hard drive, and actually noticed a difference.
Have you ever wondered why defragging helps though? This tutorial will discuss
what Disk Fragmentation is and how you can optimize your hard drive's partitions
by defragmenting them for better performance.
Fragmentation
In order to understand why defragging works, it is important to
understand how data is stored on your hard drive. When data, such as a file,
is stored on a hard drive the operating system attempts to store that file in
one section of contiguous, locations that are connecting without a break, space.
When you have a new hard drive, storing data in contiguous spaces is not a problem.
As you use the hard drive, though, files will be deleted from it and small pockets
of space will be created on your hard drive. These small pockets of space on
your hard drive is called fragmentation.
When a hard drive is fragmented, and the operating system wants
to store a file on the hard drive, it attempts to store it in a section of contiguous
space that will be large enough to accommodate the file. If the hard drive is
heavily fragmented, there is the possibility that there will not be enough contiguous
space available to store the file, and therefore the file will be broken up
and stored in multiple locations on the hard drive. This causes the file to
become fragmented. This is especially bad when installing new software on your
computer because the program will now be installed over multiple locations on
your hard drive. Now when you run this particular application its performance
will be degraded because it has to be loaded from multiple locations on the
hard drive.
Figure 1 below shows an example of a fragmented file. Notice how
File1 is stored in two locations which are not contiguous.
Figure 1: Fragmented File
Defragmentation
To solve this problem, software developers developed a type of
program called a Disk Defragmenter. A defragmenter is an application that reorganizes
the data on your hard drive's partitions in such a manner that the files are
stored in as much contiguous space as possible. The defragmenter will search
your hard drive partition and move data from one location to another location,
so that the files stored there are one contiguous piece, instead of being spread
throughout multiple locations on the hard drive's partition. This allows the
programs and data to run more efficiently and quickly as the operating system
does not have to read from multiple locations.
Figure 2 below shows an example of a file store in contiguous
space. Notice how the entire file is located in one area and not split between
multiple locations.
Figure 2: File that is not fragmented
There are two ways to defragment your hard drive. One way is to
use a Disk Defragmenter program and the other is to use an extra empty hard
drive. We will discuss both ways below.
Using the Windows Disk Defragmenter
Please Note that this tutorial will cover the defragmenter found
in Windows XP only. The other versions of windows, and other vendor's applications,
have similar programs that should not be too hard to figure out when following
this tutorial.
Step 1: Shut down all applications
It is a good procedure to shut down all applications before you
run a Disk Defragmenter including your Antivirus software. This is to make sure
that no programs attempt to write to the drive while it is being defragmented.
Though this will not cause any damage, it may cause you to have to restart the
entire process from the beginning.
Step 2: Running the Disk Defragmenter
Windows comes with a program called Disk Defragmenter which is
installed with the operating system. This program can be found in your System
Tools folder under Accessories on your Programs menu. This is shown in Figure
3 below.
Figure 3. Launching Disk Defragmenter
Click once on the Disk Defragmenter as show above in Figure 1
to launch the program. You will then be presented with a screen similar to Figure
4 below.
Figure 4. Disk Defragmenter Startup Screen
The main screen of Defragmenter will show you a listing of your
hard drive partitions and then give you the option to Analyze the partition
or Defragment it. Before you choose the Analyze or Defragment button, you should
select the partition you want to work with, by clicking once on it. By default
the first partition will be selected.
Step 3: Analyze your partitions
When you click on the Analyze button, designated by the red box
in Figure 4, the Defragmenter will scan the partition you have selected and
give you a report on how badly it is fragmented. The higher percentage that
you are fragmented, the worse it is. When it is done analyzing your hard drive
it will give you a prompt that tells you the recommendation on whether you should
defragment or not and gives you the option to defragment or view the report
as show in Figure 3 below.
Figure 5. Prompt to view Report or Defragment
I always make it a habit to view the report so I can see how badly
my hard drive is being used. You would do this by clicking on the "View
Report" button designated by the red box in Figure 5. When you click on
the View Report, you will be presented with a screen similar to Figure 6 below.
Figure 6. Report of Analysis
The report will give you a lot of details about various attributes
of your file system. We are only concerned with the Volume Fragmentation as
show in Figure 6 above designated by the red box.
Step 4: Defragmenting
NOTES: Before defragging will occur the following rules
apply:
- A partition must have 15 percent free space on the drive for the Disk Defragmenter
to work properly.
- A partition that is marked dirty will not be defragmented as it may possible
have corruption.
- You can only run one instance of Disk Defragmenter at a time.
- You can only defrag local drives.
As you can see from Figure 6 above, this computer has a total
fragmentation of 34%. That is not good and my computer is not giving me the
performance that it should be. I am therefore going to defragment my hard drive
by clicking on the Defragment button, designated by the blue box in Figure 6
above. After clicking on the Defragment button you will see a window similar
to Figure 7 below.
Figure 7: Defragging
Lets explain what you see on the screen. The two bars in the middle
of this screen with all the colors on it are the the Analysis and Defragmentation
displays.
The top bar, labeled"Estimated disk usage before defragmentation"
is the Analysis display and shows a graphical representation of your partition
before the defrag started.
The bar under it, labeled"Estimated disk usage after defragmentation"
is the Defragmentation display. This shows a real-time graphical representation
of your partition while it it going through defragmentation.
The colors on the displays, with they key designated by the blue
box in Figure 7, represent the state of the different sections of the partition.
The colors mean the following:
| Red |
Most of the clusters are part of a fragmented file. |
| Blue |
Most of the clusters are contiguous files with clusters in the group that
contain only free space and contiguous clusters. |
| Green |
Most of the clusters are part of a file that cannot be moved from its
current location for security or physical reasons. |
| White |
Most of the clusters are free space and contiguous clusters |
You should let the hard drive defrag your partition, which can
take many hours so you may want to do something else for a while. When it is
completed, it will give you a summary report and then you can shut the program
or defrag any other partitions that you may have. When you are completed you
hard drive partition should now be defragmented.
Defragmenter Software for other
Operating Systems
In general disk fragmentation is not as much of a problem for
Linux or Macintosh based computers.
Most Linux computers use the ext2 or ext3 file system which is known to
be resilient against fragmentation and is not as severely affected when it does
occur. It is advised that you do not manually defragment these types of file systems.
Macintosh based computers do not require defragmentation as much
either. Apple actually recommends
you do not defrag your drives if you are using MAC OSX as there will be little
benefit. They even state that defragging has the chance of causing a loss of
performance.
If you would still like to use a tool that works on an Apple hard
drive, the a program that is highly recommended is:
Diskwarrior
Please note that many people have reported that Norton Utilities
for Mac can actually cause problems when using their Disk Defrag utility, so
it is advised that you do not use that program for these purposes.
Using a spare hard drive to defragment
Probably the best way to defragment your hard drive, if it is
in your budget, is to use a spare hard drive. In order to defrag you would copy
all the data off the heavily fragmented drive onto a clean spare drive. You
would then delete all data on the fragmented drive, and then restore that data
back from the spare drive. This will then copy all the data back to the drive
in a clean contiguous manner.
This method will work for any operating system.
How to prevent fragmentation
There really is no way to prevent fragmentation as it is a natural
process that occurs when writing and deleting data to a hard drive. Some file
systems are more resilient to Disk Fragmentation such as NTFS and EX2. If you
are a Windows user and are not dual-booting operating systems that are not compatible
with NTFS then you should upgrade your file systems to NTFS. Not only will you
gain the benefit of a more intelligent file system but you will gain added security
benefits as well.
Conclusion
As you can see disk fragmentation can cause varying degrees of
problems depending on the operating system you use. If you are a Windows user,
then it is advised that you defragment, if you are a Linux or Mac user then
it is said to not be as important. If you do choose to defragment your hard
drives, the list of tools below can be used for the various operating systems:
Recommended Windows Defragmenter's:
Windows Disk Defragmenter
Speed
Disk
Disk
Keeper
Recommended Macintosh Programs:
Diskwarrior
As always if you have any comments, questions or suggestions about
this tutorial please do not hesitate to tell us in the computer help forums.
--
Lawrence Abrams
Bleeping Computer Basic Concepts Series
BleepingComputer.com: Computer Support & Tutorials
for the beginning computer
user.
Have a problem and would like to ask us for help? To learn how to ask your question Click Here!
Do you have popups or other malware infecting your computer? If so, Start Here!
Are you having trouble using this site? Then you should visit the New User Orientation Center!
BleepingComputer.com -> Tutorials -> Hardware Troubleshooting -> The Importance of Disk Defragmentation
