In computing, a file system or filesystem controls how data is stored and retrieved. Without a file system, information placed in a storage medium would be one large body of data with no way to tell where one piece of information stops and the next begins. By separating the data into pieces and giving each piece a name, the information is easily isolated and identified. Taking its name from the way paper-based information systems are named, each group of data is called a "file". The structure and logic rules used to manage the groups of information and their names is called a "file system".
Chiron FS is a FUSE based filesystem that implements replication at the filesystem level like RAID 1 does at the device level. The replicated filesystem may be of any kind; the only requisite is that it is mounted.
Filesystem in Userspace (FUSE) is a software interface for Unix-like computer operating systems that lets non-privileged users create their own file systems without editing kernel code. This is achieved by running file system code in user space while the FUSE module provides only a "bridge" to the actual kernel interfaces.
There is no need for special configuration files; the setup is as simple as one mount command (or one line in fstab). There is no specific communication protocol, at mount time the invoking parameters indicate two or more paths to directories which will be the replicated underlying filesystems (they must be already in sync). This allows the client to use any kind of underlying filesystems such as Ext3, NFS or SSHFS and even mix them. Every write in the Chiron FS mount point subtree will be echoed to the underlying filesystems. Any read from Chiron FS mount point subtree will be made from only one of the underlying filesystems using a prioritized round robin algorithm.
ext3, or third extended filesystem, is a journaled file system that is commonly used by the Linux kernel. It used to be the default file system for many popular Linux distributions. Stephen Tweedie first revealed that he was working on extending ext2 in Journaling the Linux ext2fs Filesystem in a 1998 paper, and later in a February 1999 kernel mailing list posting. The filesystem was merged with the mainline Linux kernel in November 2001 from 2.4.15 onward. Its main advantage over ext2 is journaling, which improves reliability and eliminates the need to check the file system after an unclean shutdown. Its successor is ext4.
If one or more underlying filesystems fails, the virtualized filesystem provided by Chiron FS continues operating as long as there is at least one replica available. In this case, the failures are reported to a log file. If the failure is on a write operation, the failed replica is disabled and it is not used by Chiron FS until it is available and resynchronized with the others. Synchronization is not implemented yet in Chiron FS, so it must be done manually. If all replica fails then the calling application receives the error message as it would receive if it was accessing a non replicated filesystem. In this case there will be no log report.
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XFS is a high-performance 64-bit journaling file system created by Silicon Graphics, Inc (SGI) in 1993. It was the default file system in SGI's IRIX operating system starting with its version 5.3. XFS was ported to the Linux kernel in 2001; as of June 2014, XFS is supported by most Linux distributions, some of which use it as the default file system.
Coda is a distributed file system developed as a research project at Carnegie Mellon University since 1987 under the direction of Mahadev Satyanarayanan. It descended directly from an older version of Andrew File System (AFS-2) and offers many similar features. The InterMezzo file system was inspired by Coda.
In computing, the Global File System 2 or GFS2 is a shared-disk file system for Linux computer clusters. GFS2 differs from distributed file systems because GFS2 allows all nodes to have direct concurrent access to the same shared block storage. In addition, GFS or GFS2 can also be used as a local filesystem.
A versioning file system is any computer file system which allows a computer file to exist in several versions at the same time. Thus it is a form of revision control. Most common versioning file systems keep a number of old copies of the file. Some limit the number of changes per minute or per hour to avoid storing large numbers of trivial changes. Others instead take periodic snapshots whose contents can be accessed with similar semantics to normal file access.
Replication in computing involves sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility.
NILFS or NILFS2 is a log-structured file system implementation for the Linux kernel. It is being developed by Nippon Telegraph and Telephone Corporation (NTT) CyberSpace Laboratories and a community from all over the world. NILFS was released under the terms of the GNU General Public License (GPL).
In Unix-like operating systems, a loop device, vnd, or lofi is a pseudo-device that makes a file accessible as a block device.
EncFS is a Free (LGPL) FUSE-based cryptographic filesystem. It transparently encrypts files, using an arbitrary directory as storage for the encrypted files.
In computer science, state machine replication or state machine approach is a general method for implementing a fault-tolerant service by replicating servers and coordinating client interactions with server replicas. The approach also provides a framework for understanding and designing replication management protocols.
A clustered file system is a file system which is shared by being simultaneously mounted on multiple servers. There are several approaches to clustering, most of which do not employ a clustered file system. Clustered file systems can provide features like location-independent addressing and redundancy which improve reliability or reduce the complexity of the other parts of the cluster. Parallel file systems are a type of clustered file system that spread data across multiple storage nodes, usually for redundancy or performance.
Btrfs is a file system based on the copy-on-write (COW) principle, initially designed at Oracle Corporation for use in Linux. The development of Btrfs began in 2007, and since November 2013 the file system's on-disk format has been marked as stable.
A journaling file system is a file system that keeps track of changes not yet committed to the file system's main part by recording the intentions of such changes in a data structure known as a "journal", which is usually a circular log. In the event of a system crash or power failure, such file systems can be brought back online more quickly with a lower likelihood of becoming corrupted.
Resilient File System (ReFS), codenamed "Protogon", is a Microsoft proprietary file system introduced with Windows Server 2012 with the intent of becoming the "next generation" file system after NTFS.
F2FS is a flash file system initially developed by Samsung Electronics for the Linux kernel.
In computing, OverlayFS is a union mount filesystem implementation for Linux.
The MapR File System is a clustered file system that supports both very
large-scale and high-performance uses. MapR FS supports a variety of interfaces including
conventional read/write file access via NFS and a FUSE interface, as well as via the HDFS interface used by
many systems such as Apache Hadoop and Apache Spark. In addition to file-oriented access,
MapR FS supports access to tables and message streams using the Apache HBase and Apache Kafka APIs as well as via a document database interface.
