File server

In computing, a file server is a computer attached to a network that has the primary purpose of providing a location for shared disk access, i.e. shared storage of computer files (such as documents, sound files, photographs, movies, images, databases, etc.) that can be accessed by the workstations that are attached to the computer network. The term server highlights the role of the machine in the client–server scheme, where the clients are the workstations using the storage. A file server is not intended to perform computational tasks, and does not run programs on behalf of its clients. It is designed primarily to enable the storage and retrieval of data while the computation is carried out by the workstations.

File servers are commonly found in schools and offices and rarely seen in local internet service providers using LAN to connect their client computers.

Contents

Types of file servers

A file server may be dedicated or non-dedicated. A dedicated server is designed specifically for use as a file server, with workstations attached for reading and writing files and databases. File servers may also be categorized by the method of access: Internet file servers are frequently accessed by File Transfer Protocol (FTP) or by HTTP (but are different from web servers, that often provide dynamic web content in addition to static files). Servers on a LAN are usually accessed by SMB/CIFS protocol (Windows and Unix-like) or NFS protocol (Unix-like systems). Database servers, that provide access to a shared database via a database device driver, are not regarded as file servers. Many file servers are simultaneously print servers too, as they provide access to printers via network. A single file serving computer may be accessible by multiple means: it may run an FTP server, an SMB server, etc., serving the same files.

Design of file servers

In modern businesses the design of file servers is complicated by competing demands for storage space, access speed, recoverability, ease of administration, security, and budget. This is further complicated by a constantly changing environment, where new hardware and technology rapidly obsolesces old equipment, and yet must seamlessly come online in a fashion compatible with the older machinery. To manage throughput, peak loads, and response time, vendors may utilize queuing theory[1] to model how the combination of hardware and software will respond over various levels of demand. Servers may also employ dynamic load balancing scheme to distribute requests across various pieces of hardware.

The primary piece of hardware equipment for servers over the last couple of decades has proven to be the hard disk drive. Although other forms of storage are viable (such as magnetic tape and solid-state drives) disk drives have continued to offer the best fit for cost, performance, and capacity.

Storage

Since the crucial function of a file server is storage, technology has been developed to operate multiple disk drives together as a team, forming a disk array. A disk array typically has cache (temporary memory storage that is faster than the magnetic disks), as well as advanced functions like RAID and storage virtualization. Typically disk arrays increase level of availability by using redundant components other than RAID, such as power supplies. Disk arrays may be consolidated or virtualized in a storage area network (SAN).

Network-attached storage

Network-attached storage (NAS) is file-level computer data storage connected to a computer network providing data access to heterogeneous clients. NAS devices specifically are distinguished from file servers generally in a NAS being a computer appliance – a specialized computer built from the ground up for serving files – rather than a general purpose computer being used for serving files (possibly with other functions). In discussions of NASs, the term "file server" generally stands for a contrasting term, referring to general purpose computers only.

As of 2010 NAS devices are gaining popularity, offering a convenient method for sharing files between multiple computers.[2] Potential benefits of network-attached storage, compared to non-dedicated file servers, include faster data access, easier administration, and simple configuration.[3]

NAS systems are networked appliances containing one or more hard drives, often arranged into logical, redundant storage containers or RAID arrays. Network Attached Storage removes the responsibility of file serving from other servers on the network. They typically provide access to files using network file sharing protocols such as NFS, SMB/CIFS (Server Message Block/Common Internet File System), or AFP.

Security

File servers generally offer some form of system security to limit access to files to specific users or groups. In large organizations, this is a task usually delegated to what is known as directory services such as openLDAP, Novell's eDirectory or Microsoft's Active Directory.

These servers work within the hierarchical computing environment which treat users, computers, applications and files as distinct but related entities on the network and grant access based on user or group credentials. In many cases, the directory service spans many file servers, potentially hundreds for large organizations. In the past, and in smaller organizations, authentication can take place directly to the server itself.

See also

References

  1. ^ File and Work Transfers in Cyclic Queue Systems, D. Sarkar and W. I. Zangwill, Management Science, Vol. 38, No. 10 (Oct., 1992), pp. 1510-1523
  2. ^ CDRLab Test (in Polish)
  3. ^ InfoStor. NAS Advantages: A VARs View, April 01, 1998. By Ron Levine.

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Look at other dictionaries:

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  • file server — file ,server noun count COMPUTING a computer that stores information that can be used by people with other computers connected to the same NETWORK …   Usage of the words and phrases in modern English

  • file server — UK / US noun [countable] Word forms file server : singular file server plural file servers computing a computer that stores information that can be used by people with other computers connected to the same network …   English dictionary

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  • file server — noun (computer science) a digital computer that provides workstations on a network with controlled access to shared resources • Topics: ↑computer science, ↑computing • Hypernyms: ↑digital computer • Hyponyms: ↑dedicat …   Useful english dictionary

  • file server — failų serveris statusas T sritis informatika apibrėžtis Duomenų laikymo įrenginys, prijungtas prie ↑vietinio tinklo ir pasiekiamas visiems to tinklo naudotojams. Į failų serverį vienu metu gali kreiptis keli naudotojai. Duomenis laiko ir tvarko… …   Enciklopedinis kompiuterijos žodynas

  • file server — file′ serv er n. cmp a computer that makes files available to workstations on a network Compare server 6) …   From formal English to slang

  • File-Server — Ein Dateiserver oder Fileserver stellt Dateisysteme oder zumindest einen Teil eines Dateisystems in einem Rechnernetz zur Verfügung. Die Hauptaufgabe eines Dateiservers ist es, mehreren Benutzern Zugriff auf Dateien zu gewähren. Die Kontrolle der …   Deutsch Wikipedia

  • File Server — Ein Dateiserver oder Fileserver stellt Dateisysteme oder zumindest einen Teil eines Dateisystems in einem Rechnernetz zur Verfügung. Die Hauptaufgabe eines Dateiservers ist es, mehreren Benutzern Zugriff auf Dateien zu gewähren. Die Kontrolle der …   Deutsch Wikipedia


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