On Thursday 18 Sep 2003 11:16 am, Paul Kaplan wrote: > Could someone please set the record straight... > Do files on ext3 filesystems get and stay fragmented? Does this degrade > performance? What tools are available to defrag? > TIA > Paul
Answers Not to any significant degree, No, and Possibly, but why bother. To give background I will explain how files are put onto Microsoft VFAT partitions and Ext3 In VFAT partitions the disc is divided into blocks. When a file is written it is divided into block sized chunks. The first block is always written to the first available block on the HD, the second goes to the next available block and so on. This means that as files are deleted holes open up in the block allocation, and subsequent files get fragmented if they are larger than the first available hole. Eventually the HD gets hopelessly fragmented and a defrag is required. By contrast Ext3 divides the HD into inodes. When a file is written to HD it is written to an area large enough to hold it as a continuous file without fragmenting. If there is no area large enough, then it gets fragmented. The effect with Ext3 is that so long as the free space on the HD is relatively large compared to the size of individual files, then fragmentation is negligible. It is only when the HD is nearly full, or you have a lot of really huge files being written/deleted you might get fragmentation. In that case I believe XFS is a better file system to use. (but am not sure why) derek -- ---------------------------------- www.jennings.homelinux.net http://twiki.mdklinuxfaq.org
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