GP.File Storage

	GP	File Storage	Version:	0.5
	Document type:	Generic Pattern	Owner:	J.A.H. Schoonderbeek

Description

This Generic Pattern belongs to "Core". This function enables a service that offers its consumers the ability to manipulate (store, retrieve and modify et cetera) data in loosely structured. The function may distribute the data over multiple logical locations, but makes its consumers view it as located in a single logical location. The function may also offer the ability to perform storage related "intelligent" tasks, such as replication, migration, encryption, reporting, compression and data deduplication.

Note that File Storage is always implemented on top of some form of Raw Storage. As a consequence, an Applied Pattern dealing with file storage is often based on both the File Storage Generic Pattern and the Raw Storage Generic Pattern.

As examples: realizations of File Storage (and Raw Storage under it) can include:

• simple Content Management Systems (CMS) and alike solutions,
• (the front-end of) NAS appliances,
• file share servers.

Note: it's possible that the solution is to make use of Business Rules (e.g. for data deduplication or automatic migration of data to nearline/offline storage). If this is to be modelled then this Pattern must be combined with the corresponding functions.

Services realized

This Pattern realizes the following service(s):

• File Storage (This service offers clients the ability to store, retrieve and modify data in loosely structured form.)

Functional and Integration view

This is the graphic representation of the functional model of this Generic Pattern:

Generic Pattern for File Storage

Generic Pattern Composition

This pattern is an aggregation of the following (mandatory and optional) functions, expressed in Generic Functions:

Icon	Function	Inclusion	Rationale
	File Engine	recommended	This function handles the actual storing/retrieving of loosely structured data such as (but not restricted to) files or documents. It serves the needs of the File Storage service's consumers such as end-users or systems (among which application engines and database servers). Note that it requires access to Raw Storage services to physically store the bits and bytes that make up the instances of loosely structured data.
	Controlling	recommended	This function can be used by authorized consumers (such as administrators and users) to change the behaviour of the Pattern.
	Caching	optional	The Pattern may use caching functionality to increase its capacity to receive and/or return data on request.

Services connected with this Generic Pattern

This Generic Pattern has the following mandatory and optional relations with adjacent Generic Services.

Service	Adjacency	Summary	Rationale
Raw Storage	recommended	This service offers to store, manipulate and read data at the level of "unstructured data".	All "loosely structured data" eventually will have to be stored on some physical device, where it is treated as "unstructured data". Placing this Service under the File Storage pattern delivers this ability.
Authentication & Authorization	optional	This service can validate an identity claim, and it can validate the permissions required for an action, as part of an Authentication & Authorization process.	A&A will be required for one or more of the following uses: permission validation for read/write/modification/deletion actions on the loosely structured data being stored; access to the more sensitive parts of the Controlling function, that may influence aspects of this Pattern's behaviour ranging from facility management to self-service provisioning of storage space;
Data Protection Management	optional	This service provides the ability to protect data against accidental or wilful corruption.	Combining this Pattern with a Data Protection Management service serves to create secondary copies of the data stored by the Pattern, with the aim of being able to perform a (partial or complete) restore of the data, in the original location or an alternative location. Note that the Data Protection Management service is usually under control of IT Operations, but may occasionally be offered to consumers directly. Depending on the way it's modelled, this may impact the Controlling function inside the Pattern.
Archive Management	optional	This service provides the ability to create and use archives.	Combining this Pattern with an Archive Management service serves to create a primary copy of the data stored by the Pattern at a different physical location. This can be to satisfy legal or other user requirements, or to free up storage space in this Pattern. Note that the Archive Management service is usually under control of IT Operations, but may occasionally be offered to clients directly. Depending on the way it's modelled, this may impact the Controlling function inside the Pattern.

Applied Patterns based on this Generic Pattern

The following Applied Patterns are based wholly or in part on this Generic Pattern: