Annotation of wikisrc/projects/project/ffs-defrag.mdwn, revision 1.1

1.1     ! dholland    1: [[!template id=project
        !             2: 
        !             3: title="Defragmentation for FFS"
        !             4: 
        !             5: contact="""
        !             6: [tech-kern](mailto:tech-kern@NetBSD.org)
        !             7: """
        !             8: 
        !             9: category="filesystems"
        !            10: difficulty="medium"
        !            11: 
        !            12: description="""
        !            13: Heavily used file systems tend to spread the blocks all over the disk,
        !            14: especially if free space is scarce. The traditional fix for this is to
        !            15: use dump, newfs, and restore to rebuild a volume; however, this is not
        !            16: acceptable for current disk sizes.
        !            17: 
        !            18: The resize_ffs code already contains logic for relocating blocks, as
        !            19: it needs to be able to do that to shrink a volume; it is likely that
        !            20: it would serve nicely as a starting point for a defragmenting tool.
        !            21: 
        !            22: Note that safety (not scrambling the volume if the system crashes
        !            23: while defragging) is somewhat tricky and critically important.
        !            24: """
        !            25: ]]

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