File Fragmentation 7088

In a message on Mon, 05 Dec 2005 20:37:49 GMT, wrote :

The 'fragmentation' of files on ext2-ext3 (at this level they are the same file system) is only an issue WRT performance when the file system free space, the fragmentation is simply a non-issue.

No. In the normal course of things -- as files are created, deleted, re-created, etc. a certian amount of data shuffling goes on. Not so much as to 'optimize performance' anything -- it just happens. So long as there is 'plenty' of free space most of the time, performance remains more or less linear over time.

What generally happens in the Linux-UNIX world is that over a period of time the disk gets mostly full. Usually, by this time, it is decided (by the owner of the machine) that maybe it is time for a newer-bigger-faster disk. Such a disk is acquired and formatted fresh, with larger parbreastions and the data is copied (disk-to-disk backup). This results in a new file system that is no longer mostly full and is completely 'defragmented' (or at least is only normally fragmented). At least this is what happens to me. Except for various special cases I usually don't have to worry about disks getting over about 90% full (of non junk files) until it is time to upgrade the disk anyway. Yes, sometimes some program barfs and fills up the disk with junk data, which can cause disk performance problems.