| This article introduces a network backup system based on the backup server, client, and storage device. The three-party architecture prevents the backup server from being involved in data backup and recovery data transmission, balances the system load and increases the system concurrency. It also describes the overall architecture of the network backup system, the backup server, backup proxy and Storage Server Subsystem functions, and communication interfaces, the network backup system based on the three-party architecture can well complete remote cold backup and recovery.
Status Quo of data backup and disaster tolerance
With the deepening of social information technology, the society is increasingly dependent on computer systems. However, traditional computer information systems are very fragile in the face of disasters such as fire, flood, earthquake, war or man-made destruction, the hardware, Data, systems, and services of computer systems are damaged to varying degrees. If a disaster occurs in a communication, financial, or military system and fails to cope with the disaster in a timely manner, restoring the system functions will cause immeasurable losses.
Research shows that, after a disaster, if information operations cannot be resumed within 14 days, 75% of the company's business will be completely suspended, and 43% of the company will no longer be able to start again, 20% of enterprises were forced to declare bankruptcy within two years. From a large amount of data, it is not difficult to see that information security is closely related to national security, national rise and fall, and the outcome of war. In the face of economic and information globalization trends, we must not only see the development opportunities it brings us, but also face up to the severe challenges it brings us.
As a basic method to improve data availability and reliability, data backup aims to quickly restore system data when it crashes. Most enterprises or organizations have their own local backup systems, but their recovery capabilities are very limited, because traditional backup mainly uses storage devices with the same geographical location as the application system for local data backup, data backup is also managed in the data center at the same time, once a disaster occurs in the entire data center, such as fire, theft, or earthquake, the backup data is also destroyed, and the backup data stored on the local storage device cannot provide any disaster recovery function, this problem is especially serious in the war. The special Disaster Tolerance system came into being.
Disaster Recovery (DR), also known as a Disaster Recovery system, is to use a specific Disaster Recovery mechanism, the computer information system that can provide normal application services to the maximum extent.
Introduction to Data Disaster Recovery and backup technology
Disaster Tolerance backup is to establish and maintain a backup storage system in a remote location, and use geographic separation to ensure the system and data can withstand catastrophic events. The Disaster Tolerance System can be divided into Data Disaster Tolerance and application disaster tolerance. Data Disaster Tolerance refers to the establishment of a remote data system that replicates key application data of the local system. In the event of a disaster, data can be quickly copied from a remote system to a local system to ensure business data integrity and consistency. Application Disaster Tolerance is higher than Data Disaster Tolerance, that is, a complete backup application system (which can be used to back up each other with the local application system) is established in a remote location, can also work with local application systems ).
After a disaster occurs, the remote application system quickly takes over or undertakes the business operation of the local application system. To design a robust disaster tolerance backup system, you must consider multiple factors, such as the size of backup/recovery data, the distance between the application data center and the backup data center and the data transmission mode, the recovery speed required in the event of a disaster, the management and investment of the Backup Data Center. There are two technical indicators to measure the degree of Disaster Recovery Backup: RPO (Recovery Point Objective) and RTO (Recovery Time Objective ).
RPO is the data recovery point objective. It mainly refers to the data loss that business systems can tolerate. RTO refers to the maximum service downtime that can be tolerated, that is, the shortest time period from the occurrence of a disaster to the restoration of service functions of the business system.
Introduction to two-party architecture and three-party architecture of the Network Backup System
Two-party architecture of the Network Backup System
Third-party architecture of the Network Backup System
Overall system framework
Backup proxy
The backup proxy runs as the background daemon on the client that needs data backup and recovery services, it listens to connection requests from the backup server, authenticates the backup server, and executesCommand. The software module structure of the backup proxy is divided into four parts:
1. module initialization
2. Backup Server Request listening Module
3. Job Processing Module
4. network communication module.
Storage Server
The storage server is responsible for storing backup data and restoring data. It manages a large number of storage devices (physical storage domains) at the rear. The storage domains can identify the file records of various storage volumes and jobs.
Stored in a storage volume in a certain format. The index of the file record is provided by the directory database of the backup server. Based on the file index, the storage server will soon find the file record. Storage Server
The software module structure is divided into five parts:
1. module initialization
2. Network Connection monitoring module
3. Job ticket Module
4. Job Processing Module
5. Network Communication Module
Backup Server
The backup server receives user input, schedules jobs, and sends job commands to the backup proxy and storage server to run jobs, receive job running message feedback and output to Web interface according to user requirements. The backup server is also responsible for managing the backup and recovery-related resources customized in the system. The backup server also manages the running information and metadata of jobs.
The software architecture of the backup server consists of five main modules: system initialization, configuration resource management, USER command interaction, job operation management, and system operation monitoring:
Overall communication process of the third-party module
The communication between the third-party subsystems is based on TCP/IP for both command transmission and data transmission. Therefore, the entire system can use the existing LAN or WAN to complete backup and recovery tasks, the overall communication process between subsystems is:
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