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This article mainly explains "what is the difference between NAS and SAN". The content in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what is the difference between NAS and SAN".

SAN connects the storage array and the server through the optical fiber switch to establish a private storage network for dedicated data storage; NAS uses network technology (TCP/IP, ATM, FDDI) to establish a private storage network by connecting the storage system and the server host through the network switch.

Common server disk types

SAS: small capacity, 300G, 600G, high price

SATA: large capacity, 4T, does not support hot plug, low price

Fake SAS: large capacity, hot swappable support, low price (that is, SATA disk with SAS interface) (disadvantage: higher failure rate than SAS)

How to distinguish between SAS and SATA mainly depends on whether the interface is separate or not.

Taking Western Digital as an example to introduce the use of disk

Advantages and disadvantages of two storage connections

1: direct-attached storage (the server has its own hard disk)

Advantages: 1: easy to use 2: directly identified as a block device. Then make partition, file system, mount access disadvantages: 1: consume the resources of this server.

2: non-directly connected storage (high performance requirements for the network, 10 Gigabit Ethernet / optical network)

Can be divided into NAS network attached storage and SAN storage area network

Advantages: 1:I/O consumption has been transferred from front-end servers to back-end storage devices 2: expansion convenience disadvantages: 1: in the past, the network will become a bottleneck, but using a 10G optical fiber card first can almost solve the problem.

NAS network attached storage

NAS server is a kind of dedicated data storage server, which is connected to the network and has the function of data storage. It is based on standard TCP/IP to realize data transmission.

Common solution techniques

NFS: realizing storage sharing among unix-like systems

CIFS: to realize storage sharing between windows and Unix-like systems. Samba is the CIFS technology adopted.

SAN storage area network

Is a high-speed network that provides data transmission between the computer and the storage system.

SAN storage, using Fibre Channel (FC) technology, connects the storage array and the server host through the FC (optical fiber) switch, and establishes an area network dedicated to data storage. Because it is a special network, it has strong expansibility, whether it is adding a certain storage space in a SAN system or adding several servers that use storage space.

At present, FC-SAN and IP-SAN are common.

FC-SAN forwards scsi protocol through fibre Channel protocol, IP-SAN forwards scsi protocol through TCP protocol, SAS disk uses serial scsi protocol, SCSI disk uses parallel scsi protocol.

Common SAN classification

FC-SAN: through the scsi protocol, through the wwwn,wwwp to locate, the optical fiber has a global unique number

IP-SAN: located through the iscsi protocol and through the ip address

The equipment needed for FC-SAN

1:FC switch

2: HBA card: (FC-HBA card, commonly known as optical fiber network card)

NAS differs from SAN in two aspects.

1: in terms of network architecture: NAS uses TCP/IP to transmit data, and SAN uses scsi or iscsi protocol

2: in terms of the implementation method of reading and writing files:

NAS is a file sharing and "file level" read and write operation based on the operating system.

The interface between computer and storage in SAN is the underlying block protocol, which is located according to the "block address + offset address" of the protocol header. The shared storage has nothing to do with the front-end operating system, and any system can identify it normally.

SAN storage network architecture diagram

After the SAN is built, the storage at the back end is directly recognized as a block device by the front end.

FC-SAN/IP-SAN topology diagram

IP-SAN only needs to turn the switch into an Ethernet switch and the HBA card into an Ethernet card.

Comparison of FC-SAN,IP-SAN,NAS,DAS

Thank you for your reading, the above is the content of "what is the difference between NAS and SAN". After the study of this article, I believe you have a deeper understanding of what is the difference between NAS and SAN, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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