Categories of storage:
Closed-Systems Storage
Open System Storage > built-in storage
> External storage > Direct attached storage (DAS, direct-attached Storage)
> Networked Storage devices > Network-attached storage (NAS, network-attached Storage)
> Storage Area Networks (SAN, Storage region Network)
1, DAS--direct-attached Storage
DAS is a short term for direct attach storage (direct-attached storage), which refers to connecting a storage device directly to a server through a SCSI interface or Fibre Channel.
DAS is a better solution when servers are geographically dispersed and difficult to interconnect remotely.
However, the storage of this method can only be accessed by the host to which it is connected, and the data cannot be shared with other hosts, while the DAS also consumes server operating system resources.
2, NAS--network-attached Storage
NAS is the abbreviation of network attached storage (Network access storage), refers to the network switch to connect the storage system and server, set up a private network dedicated to data storage.
Users access data through the TCP/IP protocol, using industry-standard file-sharing protocols, such as: nfs/http/cifs, to achieve file-level data sharing.
NAS storage makes file share access easier and faster, and can easily increase storage capacity.
Combined with a specialized file server and storage technology, NAS provides an efficient, reliable, cost-effective solution for scenarios that require a large amount of file data to be shared.
But NAS is affected by network bandwidth and network congestion, which limits the NAS's network transmission capability to some extent.
3. SAN--Storage area Network
A SAN is a short term for a storage area network, a high-speed private subnet that connects storage devices such as disk arrays, tapes, and other devices to related servers through a fibre switch, fiber optic router, and fiber hub.
The SAN consists of three parts:
connecting devices (e.g., fibre routers, fibre switches, fiber hubs), interfaces (e.g. SCSI, FC), communication protocols (e.g. IP, SCSI), respectively;
These three parts, combined with storage devices and servers, form a SAN system.
Sans provide a flexible, high-performance, high-scalability storage network environment, which can transfer a large amount of data blocks more efficiently.
The SAN also has a higher bandwidth due to the use of a fiber interface, while the San also simplifies unified management and centralized control.
4. NAS--SAN
NAS has file operations and management systems, sans
SAN is mainly high-speed information storage, NAS is biased to file sharing
Sans have only a single data storage pool, and NAS is a shared and exclusive data storage pool
NAS is a network plug-in, SAN is a channel plug-in
Efficient and scalable SAN, NAS is simple and flexible
Additional:
1, SCSI--Small computer System Interface
SCSI is the abbreviation of small computer system interface, SCSI as input/output interface, mainly used for hard disk, optical disc, tape drive, scanner, printer and other equipment.
2. FC--Fiber Channel
FC is the abbreviation for Fibre Channel and is a mature and secure solution for gigabit data transmission.
Compared to traditional SCSI technologies, FC offers higher data rates, longer transmission distances, more device connectivity support, more consistent performance, and easy installation.
DAS NAS SAN