Storing inherited knowledge in cloud computing

Storing inherited knowledge in Cloud Computing

Storage is divided into ： Memory and external memory

Memory ： Categorize computing resources

External storage ： Hard disk （ disk ）

Hard disk ： Hard disk is divided into mechanical （HDD） And SSDs （SSD）

Physical disk type

SATA disc The full name is Serial Advanced Technology Attachment,SATA（Serial ATA） The hard disk of the port is called Serial hard disk .

SATA use Serial connection mode , Serial ATA The bus uses embedded clock signals , With stronger error correction ability , Compared with the past, the biggest difference is that it can transmit instructions （ It's not just data ） Inspection , If you find that The error will be corrected automatically , To a large extent The reliability of data transmission is improved .

The serial interface also has Simple structure 、 Hot plug support The advantages of .

SAS disc

1. SAS（Serial Attached SCSI） Serial connection SCSI, It's a new generation of SCSI technology , And SATA Hard disk identical , Serial technology is used to obtain higher transmission speed , And by shortening the connecting line to improve the internal space .SAS It's parallel SCSI New interface developed after interface . This interface is designed to improve the performance of the storage system 、 Usability and scalability , And provide with SATA Hard disk compatibility .

- NL-SAS disc

1. NL-SAS Is adopted SAS Disk interface and SATA Disc body synthesis .NL-SAS The speed of the hard disk is only 7200 turn , So performance ratio SAS The hard disk is poor . But because of the use of SAS Interface , So there is an improvement in addressing and speed .

SSD disc

1. SSD（Solid State Disk）, Solid state disk , It's a hard disk made of an array of solid state electronic memory chips , Controlled by Control unit and storage unit （FLASH chip ( Flash memory )、DRAM chip （ Dynamic random access ）） form .SSD In the specification and definition of the interface 、 It has the same function and usage as ordinary hard disk , In the product shape and size is also completely consistent with the ordinary hard disk .SSD Although it has what the traditional mechanical hard disk does not have Read and write quickly 、 The quality of light 、 Low energy consumption and small size , However, its service life is limited and its price is high .

Comparison of physical disk types

Physical disk type	SSD	SAS	NL-SAS	SATA
performance	Very high	high	Higher	commonly
reliability	commonly	high	Higher	commonly
Price	Very high	high	It's cheaper	cheap
energy consumption	low	high	The lower	The lower
Application scenarios	Scenarios where data access is very frequent	Medium and high-end users with discrete data	Larger data blocks , Less business pressure	Larger data blocks , Less business pressure

Centralized storage ： There are many hard disks in the server , The content is centralized , Stored in one place

 

RAID technology ： It is called redundant disk

advantage ： Efficient parallel reading and writing of multiple disks 、 Secure parity check and hot standby Technology

Commonly used RAID type

RAID0: Also called striping . Logic multiple hard disks into one hard disk for use , At least one hard disk is required , The capacity is equal to the total capacity of all disks , But the security remains the same , The reading and writing speed increases the most

RAID1： Mirror image . Write in both hard disks at the same time , The capacity is only equal to the capacity of one of them , The reading and writing speed remains the same , High safety , At least two hard disks are required .

RAID5： Independent data disk and distributed check block . You need at least three hard drives , Take two-thirds of each disk to store things , One third do parity . Allow a bad hard disk

RAID6: At least four hard drives are required , Allow two bad hard disks

 

RAID10: yes RAID1 and RAID0 The combination of

RAID50: yes RAID5 and RAID0 The combination of

Centralized storage type

SAN: Storage area network . High speed storage independent of business network

The storage server is provided to the host through the network ,

There are two submission schemes : IP-SAN Use existing Ethernet

FC-SAN Configure the network interface and switch adapter on the storage server , Using an optical network

IP-SAN and FC-SAN contrast

	IP-SAN	FC-SAN
Network speed	1GB、10GB 、40GB	4GB 、8GB、16GB
Network architecture	Direct use of existing IP The Internet	Build optical fiber network and network separately HBA card
transmission distance	There is no limit in theory	Limited by the transmission distance of optical fiber
management 、 maintain	It's easy to operate	High technical requirements
Compatibility	With all support IP Network devices are compatible	Compatibility is poor
performance	The current mainstream is 1GB	Very high read-write and transmission performance
cost	cheap	high （ Optical switches 、HBA card 、 Train technicians ）
Security	The lower	Higher

 

NAS： It's called Network Attached Storage . Mostly used in home networks , Dedicated file storage , Equivalent to a shared directory .

Two sharing schemes

CIFS:

CIFS（Common Internet File System）, General network file system , By Microsoft Of SMB（Server Message Block） Developed from a public 、 Open file system . stay Windows Between the host , You can use a simple shared mapping , take CIFS Mount the shared resources on the server to your own system , Use it as your own local system resources

NFS：

NFS（Network File System）, Network file system , By Sun company-developed , Used in Linux/UNIX/AIX/HP-UX/Mac OS X Such as UNIX Realize network file sharing in the operating system of . Mount the remote file system under its own file system through the mount command , Use remote shared files as if they were native files

CIFS and NFS contrast

	CIFS	NFS
Transmission characteristics	Based on the Internet , High reliability requirements	Based on the Internet , Independent transmission
Ease of use	No additional software required	Need to install software
Security	Error recovery is not possible	Error recovery is possible
File conversion	Do not preserve the characteristics of file format	Preserve the properties of the file format

Distributed storage ：

Take out the free hard disk on each server , Form a centralized storage pool , Later, the server can go to this storage pool to get things

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Replica mechanism ： Ensure no data loss . A file is written in , Will split this document in two （ It's called a double copy ） Or one into three （ Called three copies ）, Stored in two or three servers . If you read, you only need to read one of them , If the host is damaged, it can be read from other servers .

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Common distributed storage products

The following two are open source

 

 

The following two are closed sources

 

 

Virtualized storage and non virtualized storage

Virtual storage ： from SAN or NAS Storage space provided , You need to add a layer of file system to shield the underlying differences , Poor performance . Support more virtualization features .

Non virtualized storage ： Space provided by distributed storage , No file system was added , Good performance , Cannot support advanced features .

Storage architecture in virtualization

 

 

pool namely Storage pool , It is a container for storing space resources , The storage space used by all application servers comes from the storage pool .

Volume namely volume , It is the internal management object of the storage system .

LUN： It is a storage unit that can be directly mapped to the host for reading and writing , yes Volume The external embodiment of the object

file system : Hierarchical organization of documents , After the operating system has a file system , Data is represented in the form of files and folders , You can copy files 、 Paste 、 Delete and restore .

Common file systems

operating system ：NTFS、ext2/3/4、FAT32、exFAT

NVS Stored file system :CIFS、NFS

Virtualize the file system of the cluster ：VIMS（ Huawei ）、VMFS（VMware）

format ： Re write to the file system

The process of mapping files to disk

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