ReiserFS
ReiserFS is a multi-purpose file system that has been in his company belonging Namesys developed and implemented by a group of developers led by Hans Reiser from 2001. The Reiser File System is subject to the General Public License. The development of version 3 was supported by MP3.com and the SuSE Linux GmbH, version 4 mainly by DARPA and Linspire.
ReiserFS was the first journaling file system that was included in the Linux kernel by default ( kernel version 2.4.1). It is mainly used for logical volumes or RAID systems.
Currently, ReiserFS is fully supported in version 3 by the Linux kernel. For FreeBSD, there is experimental support, so far only for read operations. Commercial drivers are also available for the operating systems from Microsoft.
ReiserFS, versions 1 and 2
The ReiserFS is based on the developed by Rudolf Bayer data structure of B - tree. This applies to versions 1 to 3
ReiserFS version 3
In version 3, ReiserFS a journal has been added. Originally it was a disadvantage of ReiserFS over some other journaling systems that journaling has been applied only to the meta-information, that is, for the directories and administrative sectors, but not for the user data in the files themselves. This has been fixed in the 2.6 kernel.
Reiser4
Reiser4 is a completely new development and should not be confused with a development of the old ReiserFS. Therefore, it is deliberately not marketed as " ReiserFS 4". It is a modification of the B * -tree structure used so-called Dancing Trees. The main difference is that insufficient filled nodes are not merged with any modification of the tree, but only if a writeback is required on the hard memory by memory shortage or a transaction has been completed.
A speed advantage Reiser4 into the storage of user data in the journal, since it works with a wandering journal for this. Here, the data must not be written to disk twice, first in the Journal and subsequently in the file system, they are instead written directly to the intended location in the file system and set the journal up to completion of the operation about it.
Was further added to a flexible plug-in structure can be achieved by the special meta - types, encryption, and compression. On Reiser4 there is the possibility of metadata files that contain, for example, title and artist of a music file, save it in the file system rather than in applications. The difference, for example, ID3 tags of MP3 files and similar metadata systems is that here a metadata system in the file system and is not integrated in the container format of the file, which could be the same for all files. If this approach should ever be completed, it would take no longer to pay attention to whether an application all types of metadata with which it may come into contact understands. Access to the metadata could be done transparently via the functionality of the file system. While that might improve the inter- compatibility of applications, it makes the inter- compatibility of file systems difficult because the metadata could not be on a different file system that does not have this metadata system, such as ext4, XFS or FAT32 copied. Also, NTFS supports such alternatives data streams.
Basic ReiserFS functions
Advantages over other file systems ReiserFS offers especially when handling many small files, because they can be used in the management node (such as NTFS in the MFT ) are stored. This means that the files take up less space in the file system and the space on the hard disk can be used more efficiently. These features of the file system can be defined in the parameters when mounting. The most common parameters are:
There are also the developers included programs for the management and administration of the file system, the reiserfsprogs: