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