There are three kinds of general data backup operations. One is the full backup, and all files are written to the backup media; the other is the incremental backup, only the files changed after the last backup, is the most effective backup method; three is differential backup, back up the last full full backup All documents have passed, its advantages are just
The two sets of tapes can restore the last one of the full-cut tape and the last differential backup tape. After determining the guidance ideology and backup scheme of the backup, you should select secure storage media and technology for data backup, with "cold backup" and "hot backup". The hot backup refers to the backup of "online".
That is, the downloaded backup data is also stored in the entire computer system and network, but is only stored in a business system that makes a non-work or another non-real-time service system. "Cold Backup" refers to a backup of "not online", downloaded backups stored in a secure storage medium, and this storage medium is running
The entire computer system and network are not directly contacted, reinstall when the system is restored, some of the original data is saved for a long time and used as query. The advantage of the hot spare is that the investment is large, but the call is fast, easy to use, and more advantageous when needed in system recovery. The specific practice of hot spare is:
To open a non-work running space in the host system, store backup data, ie the partition backup; another method is to back up data to another, through the transmission between the host system and the subsystem, the same speed Fast and call convenient features, but investment is more expensive. Cold backup makes up
Some of the hot spare, the two advantages complement each other, complementary, because the cold backup also has a special advantage that is convenient in the void risk. In the process of backup, backup software is often used, which generally should have the following functions. Ensure the integrity of the backup data and has the management capabilities of the backup media;
Support multiple backup mode, you can automatically back up, you can also set backup automatic start and stop dates; support multiple check methods (such as byte check, CRC cycle redundancy, fast tape scanning) to ensure backup Positiveness; provide online data backup function; support RAID fault tolerant technology and map
Like backup function.
Web service
It is a new platform for establishing interoperable distributed applications. The basis of the Web Service is XML messaging, which is passed through standard network protocol, such as HTTP. Three techniques that make up the Web Service platform:
1 XML and XSD
XML is the basic format of the data on the Web Service platform. XML Schema (XSD) defines a set of standard data types.
2 SOAP
The SOAP Simple Object Access Protocol provides a standard RPC method to call the Web Service. The SOAP specification defines the format of the SOAP message and how to use SOAP through the HTTP protocol. SOAP is also based on XML and XSD, XML is SOAP
Data encoding method.
3 WSDL
Web Service Description Language (WSDL) is based on XML-based languages for describing Web Service and its functions, parameters, and return values.
Create a simple web service method:
1 Suppliers choose their own programming language, middleware and development platform development, assemble web service;
2 Various suppliers define a Web Service Description Language (WSDL) to establish Web Service by unified language and standard;
3 Suppliers are registered in UDDI, UDDI enables suppliers to release web services, and find their software to find services provided by other vendors, which is the resource sharing;
4 Users search for him to serve him through UDDI; 5 users call the service by SOAP.
UDDI (unified description, discovery and integration)
Three roles are included in the architecture of Web Service: service providers, service requesters, service registers. There are three operations between roles: publish, lookup, and binding.
The main goal of the Web Service is cross-platform and interoperability, its characteristics:
1 intact encapsulation;
2 loose coupling;
3 Normative nature of use;
4 use standard protocol specifications;
5 highly integrated power;
6 openness.
Web Service should use:
1 Communication across firewalls;
2 application integration;
3 B2B integration;
4 software and data reuse.
UDDI (unified description, discovery, and integrated universal description, discovery, and integration)
It is a web-based, distributed, implemented standard specification for the information registry provided by Web Service, and also contains a group of web services that can provide itself to enable access to other companies. The implementation of the agreement.
The core of UDDI is UDDI commercial registration. The information provided by UDDI commercial registration includes three parts: white pages, yellow pages and green pages.
SOAP
It is a representation layer protocol based on XML, which is used to easily exchange data in the form of an application. SOAP technology helps to achieve interoperability between a large number of heterogeneous procedures and platforms, thereby enabling the existing application to be accessed by users.
Web Service Technology (SOAP, UDDI, WSDL, EBXML)
J2EE Technology (JNDI EJB JMS JavaMail JDBC JSP Servlet RMI-IIOP)
JTA Transaction JMS Message Service JAAS Security Service
According to the division of the logic layer based on J2EE specifications, the distributed programming environment is usually divided into four types:
EJB container; web container; customer application container; Applet container.
