Shulou(Shulou.com)06/01 Report--

In order to build a disaster recovery system, we must put forward the corresponding design indicators as a parameter to measure and select disaster recovery solutions.

At present, the international general evaluation standard of disaster recovery system is Share 78, which mainly includes the following contents.

Scope of ● backup / recovery

Status of the ● disaster recovery plan

The distance between ● service center and disaster recovery center

How to connect ● service center and disaster recovery center

How ● data is transferred between two centers

How much data is lost allowed by ●

● guarantees that updated data will be updated in the disaster recovery center.

The ability of the ● disaster recovery center to start the disaster recovery process

Share 78 is only an evaluation standard for establishing a disaster recovery system, and more specific design indicators need to be provided when designing a disaster recovery system. The ultimate goal of establishing a disaster recovery system is to restore data services as quickly as possible after a disaster, so the design index of the disaster recovery center is mainly related to the data recovery capability of the disaster recovery system. The most common design metrics are RTO (Recovery Time Objective) and RPO (Recovery Point Objective).

RTO and RPO are the key.

RTO is an indicator of the timeliness of business recovery, indicating the time it takes for business to return to normal from interruption. The smaller the RTO value is, the stronger the data recovery capability of the disaster recovery system is. The RTO of various disaster recovery solutions is quite different. Synchronous data replication based on optical channel technology, combined with remote standby business system and high availability management across business centers and backup centers, this disaster recovery solution has the smallest RTO. Disaster recovery system needs to invest a lot of money in order to obtain the minimum RTO.

RPO is an indicator of restoring data integrity. In synchronous data replication mode, RPO is equal to the time of data transmission delay; in asynchronous data replication mode, RPO is basically the queuing time of asynchronous data transmission. In practical application, considering the data transmission factors, the consistency (SCN) of the business database and the disaster recovery backup database is different. RPO represents the time difference between the SCN of the business database and the disaster recovery backup database. After a disaster, start the disaster recovery system to complete data recovery, and RPO is the amount of data loss of the new recovery business system. The RTO and RPO of different disaster recovery schemes are different.

Comprehensive consideration of technical indicators

The design of disaster recovery system can not only look at RTO and RPO, for different business systems and users' special requirements, some other indicators may become the main factors in choosing disaster recovery solutions. For example, in some areas, in order to guard against the risk of some specific natural disasters, disaster recovery backup centers are required to maintain a sufficient distance from the business center. In this case, the distance between the disaster recovery backup center and the business center is an important indicator of the disaster recovery system.

Most business systems are database application structures, and business system disaster recovery is actually database disaster recovery. The difficulty of realizing database disaster recovery is to ensure the consistency of the database all the time. In order to ensure that the disaster recovery backup database can be opened and run at any time, the availability of the disaster recovery backup database must be checked. As most of the disaster recovery technologies use logical volume data replication, it is difficult to ensure the consistency of the disaster recovery backup database at all inspection time points, so it is possible to fail in a single test, so it has to be checked repeatedly. It is necessary to take the test success rate of disaster recovery backup database as the design index of disaster recovery system.

The communication network is a part of the disaster recovery system, and the quality of the communication line is also one of the performance indicators of the disaster recovery system, including the network data transmission bandwidth, the redundancy of the network transmission channel and the service level of the network service provider (network annual outage rate). If the communication network used by the disaster recovery system is determined, in order to compare different disaster recovery solutions, the complete data recovery time of the database per unit storage capacity on the same communication network can be used as a design index.

If the disaster recovery system is required to have the ability to prevent all kinds of disasters, especially the ability to resist man-made destruction, the data backup of the disaster recovery system needs to be taken as a design index. This is because all the artificial damage to the business center through the network and the misoperation of the management staff will also affect the disaster recovery backup center. Only by using the method of offline data backup can we prevent man-made disasters.

The best is not the best.

From an economic point of view, the best disaster recovery solution is not necessarily the best disaster recovery solution. The total investment (TCO) and return on investment (ROI) of the disaster recovery system are very important design indicators for many users. TCO includes the total investment in establishing, maintaining and expanding the system. As the probability of using disaster recovery system is very low, the development of new technology and the improvement of performance-to-price ratio of new products will inevitably lead to the devaluation of disaster recovery equipment. Therefore, for disaster recovery systems, the higher the TCO, the lower the ROI.

In the process of upgrading the IT system, new technologies and new products will be adopted, and any change in the business system will lead to corresponding changes in the disaster recovery system, which is bound to increase the investment in system upgrade. In order to minimize the impact of this change, the flexibility and compatibility of the disaster recovery system should also be a very important indicator.

To sum up, when designing a disaster recovery system, we must take into account various factors such as geographical environment, network conditions, investment scale, long-term development planning of the business system, etc., according to the use of the user's business system. Develop reasonable and feasible disaster recovery system design indicators.

(E5) RPO and RTO of different disaster recovery solutions

Reference: http://www.360doc.com/content/16/1218/22/39197078_615851313.shtml

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.