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Chapter 14. Glossary

Brick
A Brick is the GlusterFS basic unit of storage, represented by an export directory on a server in the trusted storage pool. A Brick is expressed by combining a server with an export directory in the following format:
SERVER:EXPORT
For example:
myhostname:/exports/myexportdir/
Cluster
A cluster is a group of linked computers, working together closely thus in many respects forming a single computer.
Distributed File System
A file system that allows multiple clients to concurrently access data over a computer network.
Filesystem
A method of storing and organizing computer files and their data. Essentially, it organizes these files into a database for the storage, organization, manipulation, and retrieval by the computer's operating system.
Source: Wikipedia
FUSE
Filesystem in Userspace (FUSE) is a loadable kernel module 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.
Source: Wikipedia
Geo-Replication
Geo-replication provides a continuous, asynchronous, and incremental replication service from site to another over Local Area Networks (LAN), Wide Area Network (WAN), and across the Internet.
glusterd
The Gluster management daemon that needs to run on all servers in the trusted storage pool.
Metadata
Metadata is data providing information about one or more other pieces of data.
Namespace
Namespace is an abstract container or environment created to hold a logical grouping of unique identifiers or symbols. Each Gluster volume exposes a single namespace as a POSIX mount point that contains every file in the cluster.
Open Source
Open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology.
Before the term open source became widely adopted, developers and producers used a variety of phrases to describe the concept; open source gained hold with the rise of the Internet, and the attendant need for massive retooling of the computing source code.
Opening the source code enabled a self-enhancing diversity of production models, communication paths, and interactive communities. Subsequently, a new, three-word phrase "open source software" was born to describe the environment that the new copyright, licensing, domain, and consumer issues created.
Source: Wikipedia
Petabyte
A petabyte (derived from the SI prefix peta- ) is a unit of information equal to one quadrillion (short scale) bytes, or 1000 terabytes. The unit symbol for the petabyte is PB. The prefix peta- (P) indicates a power of 1000:
1 PB = 1,000,000,000,000,000 B = 10005 B = 1015 B.
The term "pebibyte" (PiB), using a binary prefix, is used for the corresponding power of 1024.
Source: Wikipedia
POSIX
Portable Operating System Interface (for Unix) is the name of a family of related standards specified by the IEEE to define the application programming interface (API), along with shell and utilities interfaces for software compatible with variants of the Unix operating system. Gluster exports a fully POSIX compliant file system.
RAID
Redundant Array of Inexpensive Disks (RAID) is a technology that provides increased storage reliability through redundancy, combining multiple low-cost, less-reliable disk drives components into a logical unit where all drives in the array are interdependent.
RRDNS
Round Robin Domain Name Service (RRDNS) is a method to distribute load across application servers. RRDNS is implemented by creating multiple A records with the same name and different IP addresses in the zone file of a DNS server.
Trusted Storage Pool
A storage pool is a trusted network of storage servers. When you start the first server, the storage pool consists of that server alone.
Userspace
Applications running in user space don’t directly interact with hardware, instead using the kernel to moderate access. Userspace applications are generally more portable than applications in kernel space. Gluster is a user space application.
Volfile
Volfile is a configuration file used by glusterfs process. Volfile will be usually located at /etc/glusterd/vols/VOLNAME.
Volume
A volume is a logical collection of bricks. Most of the gluster management operations happen on the volume.