Cromfs

Cromfs is a compressed read-only filesystem for Linux. Cromfs is intended for permanently archiving gigabytes of big files that have a lot of redundancy. It is more aimed at heavy compression than at a light fingerprint.

Features:

• Data, inodes, directories and block lists are stored compressed
• Duplicate inodes, files and even duplicate file portions are detected and stored only once
• Especially suitable for gigabyte-class archives of thousands of nearly-identical megabyte-class files.
• Files are stored in solid blocks, meaning that parts of different files are compressed together for effective compression
• Most of inode types recognized by Linux are supported (see comparisons).
• The LZMA compression is used. In the general case, LZMA compresses better than gzip and bzip2.
• As with usual filesystems, the files on a cromfs volume can be accessed in arbitrary order; the waits to open a specific file are small, despite the files being semisolidly archived.

What is new in this release:

• This release fixes a crashing bug in mkcromfs relating to storing decompressed temporary fblock files.

What is new in version 1.5.8:

• This release fixes some minor bugs and improves the performance of mkcromfs significantly in many aspects.

What is new in version 1.5.6:

• This release adds OpenMP-using parallelization to various operations in mkcromfs, causing a speedup of at least 30% on multi-core platforms.
• The effectiveness of the automatic index was also improved.
• A bug that caused a potential crash to occur when a certain combination of command-line options was used in mkcromfs was also fixed.

What is new in version 1.5.5.3:

• This relatively minor release addresses two major bugs in recent releases of Cromfs: A data corruption bug in mkcromfs, and compilation problems on 32-bit platforms.
• All users of Cromfs versions 1.5.4.2 or later are urged to upgrade.

What is new in version 1.5.5.1:

• This release has a number of performance optimizations and bugfixes.

Requirements:

• GNU make and gcc-c++ are required to recompile the source code.
• The openssl development library is required for MD5 calculation.
• The filesystem works under the Fuse user-space filesystem framework. You need to install both the Fuse kernel module and the userspace programs before mounting Cromfs volumes.
• You need version fuse version 2.6.0 or newer. (2.5.2 might work.)