Q: What is the difference in defragmentation for FAT and NTFS?A: The architecture of these two file systems is completely different and without going into details, both suffer from fragmentation in their own way. What is important is how to solve the problem for each. FAT has always needed defragmentation and many tools are available for FAT. Microsoft has included a utility in Win 95 and this does a fine job. There is just one drawback, it does defragging in "batch-mode". This means it takes the system for itself and nothing else can run while the disk is being defragmented. In an NT production environment this is in quite a few cases impossible to do. So for an NT (server) production environment, often an on-line (as opposed to batch-oriented) solution needs to be chosen. Q: What is the MFT and why does it fragment also?A: NTFS keeps a record of each file in the Master File Table. This MFT is a normal file and can also get fragmented. It will expand when more file records are added. When free space is fragmented, the MFT will be written in separate parts and it will take more time to find the file records. It is important to keep NTFS disks defragmented right from the start to keep the MFT from fragmenting too heavily and causing performance degradation. Q: How much performance am I losing due to fragmentation?A: It depends very much on what kind of environment you are running. A Win NT Workstation NTFS system that does not hammer the hard disk a lot will not suffer too much. It may not even be noticeable. But after a while, say three to six months, things do slow down gradually. The time you are losing while waiting for the disk will never be recovered. On an NT server with a lot of users it is strongly recommended to defragment from the first day of use. Q: After analyzing or defragmenting my NTFS partition, Diskeeper reports that I have less free space as a percentage than I really have. Why is Diskeeper not reporting the correct amount of free space?A: The ''Free Space Available for Defragmentation'' message refers to the free space area outside of the 12.5% set aside for expansion of the MFT. For instance, if the ''Free Space Available for Defragmentation'' figure is 17%, the total free space would be around 29.5%. The MFT area is indicated by the green and white striped area in the graphic display. Diskeeper can’t move files into this area under any circumstances. You can look in the Text selection of the View menu to see what the total free space and free space percentage are. By the way, you will find that the Report View displays the exact same percentage free space that you will find in Windows NT under the Volumes selection of the View menu in the Disk Administrator (one of the few ways that Windows NT reports percentage free space.) On Windows 2000 systems, you can find this percentage by selecting Control Panel \ Administrative Tools \ Computer Management \ Disk Management. Q: I think that fragmentation is an issue that I would like to solve, but the price for these utilities is difficult to justify to my boss, any suggestions?A: The best way to approach this is simply take the lost time of your users as a cost factor. Suppose you have 40 users on an NT File-Print Server. The main use is a shared database. 35% disk I/O slowdown could easily cost per user about 5-10 minutes per day. We're being conservative so lets say 5 minutes times 40 = 200 minutes. Let's round down and say it costs 3 working hours (180 minutes) a day. The total cost to the company for one working hour is say 15 bucks. Cost of Fragmentation per day is $ 45. That makes the payback time for a 400 dollar product about 9 to 10 days. After that you are starting to make money and gain productivity. Any MIS manager can free up budget for that! More Information
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