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Files management

File Systems

ext3

Reserved blocks

By default ext3 reserved 5% of disk space to super-user. The intent is to let the ability to critical applications to write to the disk when it is full, but it has no use for a data partition, you just waste 5% of your partition.

You can remove these reserved blocks with the following command:

tune2fs -r 0 /dev/sda1

Duplicates

  • geekie for images (fork of gqview)
  • fdupes
  • fslint

Secure delete

  • secure-delete (srm, sfill, sswap, smem)
    • -l option to be a lot faster: 2 passes instead of 38 (or -ll for only 1 pass), enough to prevent the use of consumer tools like photorec, but not for specialized companies and governments ;-)
  • shred (less advanced but more common)

Data recovery

First unmount your partition and remount it read-only.

  • testdisk (photorec)
  • ext3grep
    ext3grep <partition> --restore-file <filename> # filename => file ; works great, but only for one file at a time...
    ext3grep <partition> --restore-all --deleted --after=1270639550 # dates -> files
    ext3grep <partition> --histogram=dtime --deleted --after=1270639000 --before=1270640000 # => dates
    ext3grep <partition> --ls --inode 2 # filenames => inodes (navigating in directories with inodes)
    ext3grep <partition> --search Libs/jafar/modules/ # filename,dates -> blocks
    ext3grep <partition> --restore-inode <inode> # inodes => files

    Notes: “restore-all” failed while building stage2 cache with error “ext3grep: init_directories.cc:535: void init_directories(): Assertion `lost_plus_found_directory_iter != all_directories.end()' failed.”. However doing a “ls inode” created this stage2 cache, and afterwards “restore-all” worked… but just restored everything on the disk even not deleted files/dirs, not taking into account the “after” option… But manually editing the stage2 cache to only keep files/dirs you want to restore then “restore-all” worked perfectly!

software/files.1273401461.txt.gz · Last modified: 2013/09/19 16:43 (external edit)
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