mirror of https://github.com/ventoy/Ventoy.git
88 lines
3.5 KiB
Groff
88 lines
3.5 KiB
Groff
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SQUASHFS 2.1 - A squashed read-only filesystem for Linux
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Copyright 2004 Phillip Lougher (plougher@users.sourceforge.net)
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Released under the GPL licence (version 2 or later).
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Welcome to Squashfs version 2.1-r2. Squashfs 2.1 introduces indexed
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directories which considerably speed up directory lookup (ls, find etc.) for
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directories which are greater than 8K in size. All directories are now also
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sorted alphabetically which further speeds up directory lookup. Many smaller
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improvements have also been made to this release, please see the CHANGES file
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entry for detailed changes.
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1. DIRECTORY SPEED IMPROVEMENT EXAMPLES
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---------------------------------------
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To give an indication of the directory speed improvements a number of test
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results are shown here. There is in addition a new PERFORMANCE.README file
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which gives details of I/O and lookup performance for Squashfs 2.1 against
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the Zisofs, Cloop and CRAMFS filesystems.
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example 1:
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Filesystems generated from a single directory of 72,784 files (2.6 MB
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directory size). Each file is 10 bytes in size (the test is directory
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lookup and so the file size isn't an issue). The ext3 uncompressed
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directory size is 288 MB (presumably because of one file per block).
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Zisofs compressed size 153.50 MB
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Cloop (isofs) compressed size 1.74 MB
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Squashfs2.1 compressed size 612 KB (0.60 MB)
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Time taken to perform "ls -lR --color=always | cat > /dev/null" on
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filesystems mounted on hard disk.
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Zisofs 35 minutes 7.895 seconds (User 7.868 secs, Sys 34 mins 5.621 secs)
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Cloop 35 minutes 12.765 seconds (User 7.771 secs, Sys 34 mins 3.869 secs)
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Squashfs2.1 19 seconds (User 5.119 secs, Sys 14.547 secs)
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example 2:
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Filesystems were generated from the Ubuntu Warty livecd (original uncompressed
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size on ext3 is 1.4 GB).
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Zisofs compressed size 589.81 MB
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Cloop (isofs) compressed size 471.19 MB
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Squashfs2.0 compressed size 448.58 MB
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Squashfs2.1 compressed size 448.58 MB
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Time taken to perform "ls -lR --color=always | cat > /dev/null" on
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filesystems mounted on hard disk.
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Zisofs 49.875 seconds (User time 2.589 secs, Sys 11.194 secs)
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Cloop 20.797 seconds (User time 2.706 secs, Sys 13.496 secs)
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Squashfs2.0 16.556 seconds (User time 2.424 secs, Sys 10.371 secs)
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Squashfs2.1 10.143 seconds (User time 2.475 secs, Sys 4.440 secs)
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NOTE: the usual warnings apply to these results, they are provided for
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illustrative purposes only, and due to different hardware and/or file data, you
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may obtain different results. As such the results are provided "as is" without
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any warranty (either express or implied) and you assume all risks as to their
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quality and accuracy.
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2. NEW MKSQUASHFS OPTIONS
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-------------------------
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There is only one extra option "-2.0". This tells mksquashfs to generate
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a filesystem which is mountable with Squashfs version 2.0.
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3. APPENDING AND MOUNTING SQUASHFS 2.0 FILESYSTEMS
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--------------------------------------------------
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Mounting 2.0 filesystems is supported by Squashfs 2.1. In addition
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mksquashfs v2.1 can append to 2.0 filesystems, although the generated
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filesystem will still be a 2.0 filesystem.
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4. DONATIONS
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------------
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If you find Squashfs useful then please consider making a donation,
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particularly if you use Squashfs in a commercial product. Please consider
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giving something back especially if you're making money from it.
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Off the Squashfs subject somewhat I'm currently looking for another
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job doing Linux kernel or filesystems work. If you know of any such
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work that can be performed from the UK then please get in touch. Thanks.
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