ReiserFS is a journaling filesystem. It is very good at dealing with large numbers of small files. ReiserFS stores as many files as will fit into a single block of data, unlike most other filing systems. Compared to other filing systems, this saves disk space, especially when working with lots of relatively small files.
Future of ReiserFS
Currently there are 2 main versions of ReiserFS, 3.6 and 4, where 3 is the stable branch.
Version 4 is a rewrite of the old 3.* versions. The most popular improvement is a plug-in system, which makes it possible to encrypt, compress or do whatever else through the actual filing system, and not use an external program (see filesystem encryption). Another improvement is the new dancing trees algorithm that is better than the balanced trees -algorithm in 3.* versions. Version 4 is also fully atomic.
As of 2008, ReiserFS 4 has not been included in Linux, due to many kernel developers who think a lot of ReiserFS 4's features should not be in the filesystem, but the kernel VFS layer. Also, due to legal problems with this filesystems main developer, there is lots of doubts about the future of ReiserFS, especially as other filesystems improve, and less people maintain the ReiserFS code of any version.
How to use it
- mkfs.reiserfs - create a reiserfs partition (aka "formatting")
- fsck.reiserfs - repair a reiserfs partition
Resizing an unmounted reiserfs (growing or shrinking) is possible with the command resize_reiserfs. This command also allows for growing a mounted reiserfs. Resizing an unmounted filesystem is called offline resizing, resizing a mounted filesystem is called online resizing. For a growing operation, there must be space left on the partition where the file system resides on. For a shrinking operation, there must obviously be space left in the file system.