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What does remote disaster recovery backup mean? Many novices are not very clear about this. In order to help you solve this problem, the following editor will explain it in detail. People with this need can come and learn. I hope you can gain something.

Remote disaster recovery backup, as the name implies, is to build one or more of the same applications or databases in different regions and take over immediately after a disaster. this method plays a role in enterprise application and database security, business continuity and so on.

Advantages of remote disaster recovery and backup

1. Storage centralization. Online real-time backup is usually adopted, which can not only improve the efficiency of administrators, but also reduce the demand for complex equipment.

2. Centralization of management. Take Xirui's remote disaster recovery scheme as an example, it can enable users to achieve real-time management and overall system strategy, and network administrators can use browsers to manage data storage and avoid a lot of repetitive work.

3. Strong interoperability. In the remote disaster recovery solutions of various manufacturers, most of them can integrate different heterogeneous storage environments, that is, they can make use of existing storage devices and support a variety of storage architectures such as NAS, IP SAN, FC SAN and so on.

Remote disaster recovery backup function

1. Remote mirroring technology

Remote mirroring technology is used in data backup between the primary data center and the backup center. Remote mirror, also known as remote replication, is not only the core technology of disaster recovery backup, but also the basis of maintaining remote data synchronization and disaster recovery. Remote mirrors can be divided into synchronous remote mirrors and asynchronous remote mirrors according to whether the host requesting the mirror needs confirmation information from the remote mirror site.

Synchronous remote mirroring (synchronous replication technology) refers to replicating local data to different places in a completely synchronous way through remote mirroring software. Every local Icano transaction has to wait for the confirmation of the completion of the remote replication before it is released. Synchronous mirroring enables remote copies to always match what is required by the local machine. When the primary site fails and the user's application switches to the backup alternative site, the mirrored remote copy can ensure that the business continues without data loss. However, it has the disadvantage of long delay caused by round-trip propagation, and it is only used in relatively short distances.

Asynchronous remote mirroring (asynchronous replication technology) ensures that the basic Icano operation to the local storage system is completed before updating the remote storage view, while the confirmation information of the Icano operation provided by the local storage system to the requesting mirror host is completed. Remote data replication is carried out in the way of background synchronization, which makes little impact on the performance of the local system, long transmission distance (up to more than 1000 kilometers) and small requirements for network bandwidth. However, the writes of many remote slave storage subsystems have not been confirmed, and data consistency problems may occur when some factor causes data transmission failure. In order to solve this problem, data is updated.

2. Snapshot technology

Remote mirroring technology is often combined with snapshot technology to achieve remote backup, that is, the data is backed up to the remote storage system through mirroring, and then the snapshot technology is used to back up the information in the remote storage system to the remote tape library and CD library.

Snapshot is to quickly scan the data of the disk subsystem to be backed up by the software, and establish a snapshot logical unit number LUN and snapshot cache to back up the data. during the fast scan, the data blocks to be modified in the backup process are quickly copied to the snapshot cache. A snapshot LUN is a set of pointers to the snapshot cache and the immutable blocks in the disk subsystem (during backup). In the normal business at the same time, the use of snapshot LUN to achieve a complete backup of the original data. It enables users to extract current online business data in real time under the condition that normal business is not affected. Its "backup window" is close to zero, which can greatly increase the continuity of the system business and provide a guarantee for the real 7 × 24 operation of the system.

Snapshot uses memory as buffer (snapshot cache), and snapshot software provides real-time data image of system disk storage. It has the problem of buffer scheduling.

3. Interconnection technology

In the early days, the data backup between the primary data center and the backup data center was mainly based on SAN remote replication (mirroring), that is, through fibre Channel FC, the two SAN were connected for remote mirroring (replication). When a disaster occurs, the backup data center replaces the primary data center to ensure the continuity of the system. This remote disaster recovery backup method has some defects, such as high cost, poor equipment interoperability, short geographical distance (10 km) and so on. These factors hinder its further promotion and application.

A variety of remote data disaster recovery backup technologies based on IP SAN. They use the interconnection protocol of SAN based on IP to remotely copy the information in the primary data center SAN to the backup center SAN through the existing TCP/IP network. When the amount of data stored in the backup center is too large, snapshot technology can be used to back up it to the tape library or CD library. This kind of remote disaster recovery backup based on IP SAN can span LAN, MAN and WAN, has low cost and good scalability, and has a broad development prospect. IP-based interconnection protocols include: FCIP, iFCP, Infiniband, iSCSI and so on.

4. Virtual storage

In some disaster recovery solution products, virtual storage technology is also adopted, such as Xirui remote disaster recovery scheme. Virtualized storage technology has created a new situation in terms of system flexibility and scalability. It concatenates several different storage devices, such as IDE or SCSI drives, into a storage pool. The entire storage capacity of a storage cluster can be divided into multiple logical volumes and managed as virtual partitions. Storage thus becomes a function rather than a physical attribute, which is the main limitation of a server-based storage structure.

The virtual storage system also provides the ability to dynamically change the size of logical volumes. In fact, the capacity of storage volumes can be increased or decreased online at will. You can change the size of logical volumes in a cluster by increasing or decreasing the number of physical disks in the system. This feature allows the capacity of the volume to change dynamically according to the immediate requirements of the user. In addition, storage volumes can be easily changed, moved, and replaced. When you install the system, you only need to allocate the minimum capacity for each logical volume and leave the remaining space on the disk. With the development of the business, you can use the remaining space to expand the logical volume as needed. You can also transfer data online from the old drive to the new drive without interrupting the service.

A key advantage of storage virtualization is that it allows heterogeneous systems and applications to share storage devices, regardless of where they are located. The company will no longer need to connect a tape device to each branch's server.

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