Feature #5295

use lzma compression

Added by Tails 2013-07-18 07:38:42 . Updated 2013-07-19 02:02:53 .

Status:
Resolved
Priority:
Normal
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0%

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Type of work:
Code
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Description

As highlighted by grml’s documentation, LZMA compression of the squashfs lowers the generated images’ size by more than 10%.

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Current status

This was implemented in the feature/lzma Git branch and was merged into the devel branch => done in Tails 0.8.

  • Linux kernel: Squashfs LZMA support is now in mainline (2.6.38-rcX) in the guise of Squashfs XZ - XZ is LZMA2 which is the successor to LZMA. Current Debian unstable kernels (2.6.39 and later) support it.
  • Userspace tools: squashfs-tools 4.2 adds support for XZ compression. It is available in squeeze-backports.
  • Debian Live: exporting MKSQUASHFS_OPTIONS='-comp xz' into the build environment (in auto/build) works.
  • The build documentation now explains how to opt-out from XZ compression.

Test results

Results listed bellow are the resulting ISO images size.

20110423 - devel branch

  • default compression: 680MB
  • XZ compression: 585MB

Resources

Subtasks

History

#1 Updated by intrigeri 2013-07-19 02:02:53

  • Type of work set to Code

Type of work: Code