Network Attached Storage

Network Attached Storage (NAS, English for grid-connected storage ) simply referred to-manage file server. General NAS is used to provide minimum effort, independent of storage in a computer network.

Disambiguation, definition

Today's personal computers usually have a hard disk storage that is built directly into the computer case, and deposit their directories and files. One speaks of the computer directly associated memory ( Direct Attached Storage), which is only available to users in general, who work directly on the computer.

If a hard disk with the files stored thereon a network-wide available, so be accessible from all hosts on the network, the storage system must first be connected directly to the network and additionally control methods, which highlight the files to that location in the connected computer network. This functionality is provided by file-based networking protocols such as SMB / CIFS and NFS or block-based network protocols such as iSCSI and FCoE. This is called " memory that is connected to a network ", ie Network Attached Storage or NAS shortly. NAS systems are thus connected directly to the network and work autonomously, ie without a dedicated PC or server need to. The file systems on the NAS, so there all created files and directories that appear on the target system as an integrated release or a local file system.

NAS systems in the strict sense are server services that make the printer connected via a network service clients depends on operating system ready to use file systems. This separates the service from Direct Attached Storage and Storage Area Network. NAS systems in the broader sense, as they are offered in practice, provide centralized storage on disk arrays with both file-based and block-based with access over the general network. The overall network is usually the Ethernet - based LAN, increasingly, Wi-Fi.

Functions

A NAS generally provides file server functions. By this is meant the place via a local network users to access data files. Especially when used in a professional environment, systems must be able to access rights ( ACL) to take into account the net registered users ( Privacy Policy ). A common appearance are personal data that is only accessible by a user, or group data that are accessible for groups of multiple users.

A NAS is therefore usually much more functions than to allocate only a computer memory over the network. Therefore, a NAS in contrast to direct-attached storage is always either a stand-alone computer (host) or a Virtual Machine (Virtual Storage Appliance, VSA short ) with its own operating system. Therefore, many systems also dominate RAID functions to protect against data loss due to defects. File-based services such as NFS or SMB / CIFS are the core function dar. Some extensive NAS implementations such as FreeNAS, Open Media Vault or Openfiler dominate additional block-based data access as they are common in DAS or SAN, and provide this an iSCSI implementation. This functionality is often summarized in the phrase Filer.

For use in a small home and called SoHo networks, Network Direct Attached Storage is designed with additional features that go beyond the concept of the Filer, for example, a printer server. Some of these functions, however, are limited to small networks with few computers because depending on the system special device drivers on each connected computer are necessary.

Interfaces

The connection to NAS systems today is usually made via Ethernet and TCP / IP. By that arise in TCP / IP protocol overhead to a somewhat lesser suitability for remote mass storage results at the operating system level, so that you will not normally install SQL Server and similar performance-intensive server on NAS -based storage (see Storage Area Network ).

In particular NAS systems that are not corporate, but are designed for home or SOHO use for those who can usually be easily set up via a web interface and configure.

Benefits

NAS for business use can handle very large data sets. Through the use of powerful hard drives and also caches large amounts of data can be quickly accessed to the user. Professional NAS solutions are suitable for the consolidation of file services in enterprises. High performance, redundant and failsafe NAS solutions are an alternative to traditional Windows / Linux / Unix file servers dar. In order to simplify data backup of large NAS environments, most devices of this class support the Network Data Management Protocol ( NDMP ).

Even for households, there are a number of advantages. So all users can access the network on the same data. Alternatively, a NAS also be used as a backup solution for existing computers.