What is File System Fragmentation and why is keeping it optimized important?

What is File System Fragmentation and why is keeping it optimized important?

This article explains file fragmentation, how it affects system performance and why keeping file system optimized is important.

Some operating systems are much better at keeping their data organized than others. Each hard disk is formatted with a specific file system based on the operating system used. The file system layer on the hard drive is not something permanent the hard drive can be reformatted many times and a new file system installed. Some of the more common file systems formats used today are Fat32, and NTFS developed and used by Microsoft, Ext2 and Ext3 used by Linux, and HFS used by Apple. We won’t get into the details of file system characteristics and limitations at this time to keep things simple.

How does fragmentation start?

When data is being written to a hard drive’s file system, the system looks for free space large enough to accommodate the total size of the data being written to the drive in containers called Blocks or Clusters. Ideally the data needs to be written together, one block or cluster after another otherwise known as contiguous. This sequential location of the data on the drive makes it much easier and faster for the data to be read back by the system when needed. It also reduces the likelihood of data corruption or read errors.

I have always liked using the analogy of book in representation a hard drive and a person in representation of the read and write system. When you go out and buy a book and open it up to read it, the pages are new, and everything is organized with a table of contents, numbered pages, and even sorted by chapters. It makes sense and is very easy to read. Now imagine taking that book, ripping out all the pages and then putting them back into the book in a random order. It would likely not be easy to read, because you would have to find the next page by looking for the page number wasting lots of time skipping over pages you don’t need now. That essentially defines file system fragmentation.

In order to fix the book you would resort and organize the pages and put them back into the book in order so you could quickly and easily read them again, assuming no pages are damaged or missing. This is exactly what defragmenting a hard drive is.

Some older operating systems did not do a very good job of keeping their file systems optimized and required the user to be vigilant by doing their own monitoring and manually running defragmentation tools when they noticed performance problems occurring. This constant state of corrective repair often meant that systems were neglected by users for years. Files systems could get so badly damaged that no amount of defragmentation could repair the damage. The preinstalled tools that came with the operating system are very limited in features and might only be able to optimize only a percentage of the drive before giving up all together, if problems were too difficult to repair. These problems lead to many commercial products on the market better built to deal with file system repair and optimization. No matter which tool is used it can take a significant amount of time to defragment a hard drive depending on how much data is on the drive and how badly it is fragmented.

Today, current operating systems tools are far better at being proactive by keeping their file systems continuously monitored and optimized, so that minimal intervention from the user is required and system performance and stability is maintained regularly.

If you think your system is running much slower than it once did maybe it’s time to check your hard drive’s file system status. One way to do this in Windows, you can simply right click on the hard drive you want to check, choose “Properties” from the Menu, and then select “Tools” tab, on this screen you will a button for “Defragment now…”, from here it will give you information on the status of the drive, such as percent of fragmentation and if defragmentation is recommended. Most Operating systems will give a graphical representation of the File system fragmentation and will usually represent the fragmented data with the color red, which will make it easy to recognize and if you notice the graphical representation of your hard drive’s file system has a large amount of red on it and its scattered all over the drive, then its most likely time for you to defragment your file system to optimize your systems performance. (See the Provided sample photo for a very basic simple representation.)


Paul Comtois is a Client Support Specialist at Triella, a technology consulting company specializing in providing technology audits, planning advice, project management and other CIO-related services to small and medium sized firms. Paul can be reached at 647.426.1004. For additional articles, go to www.triella.com/publications. Triella is a VMware Professional Partner, Microsoft Certified Partner, Citrix Solution Advisor – Silver, Dell Preferred Partner, Authorized Worldox Reseller and a Kaspersky Reseller.

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