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How to protect data from loss

Protect data from loss, which can be divided into multiple levels of protection. These levels are divided according to the availability of the data, including RTO (recovery time goal: time required to recover the system) and RPO (recovery Point objective: acceptable amount of data loss).

The higher the level of protection, the less RTO and RPO, but the higher the relative cost of implementation. These levels are backup, local replication, remote replication, and real-time continuous replication.

1. Backup

Backup is for data recovery in the event of a system failure, including tape backup and disk backup.

Tape backup (B2T backup To Tape) is a classic backup method, which backs up data to tape. Tape backup has the advantages of large capacity and low cost, but it takes a long time for backup and recovery, and the probability of successful recovery is small.

Disk backup (B2D, Backup To Disk) refers to the disk array as a backup device, which improves the performance of backup and recovery, and provides high reliability and availability.

Virtual tape library (VTL, Virtual Tape Library), also known as disk library (Disk Library), uses disks to store data and can be simulated as a physical tape library. This backup method is the mainstream way of disk backup, and its advantages are: the performance of tape backup is greatly improved; at the same time, it can also follow the original tape backup software and backup strategy.

There are also some derivative backup methods, such as B2D2T backup To Disk Library To Tape, which first backs up to the virtual tape library, and then to the tape. In this way, the storage space can be fully utilized and the information can be stored on the appropriate storage device. Now that the amount of data is getting larger and larger, it must take a lot of work if you still choose to back up on disk. Therefore, there are a lot of cloud backup products on the market. For example, multiple backups can achieve one-click backup, recovery and migration of enterprise, APP and website data. All the data are encrypted by the international AES high-strength encryption algorithm, and the data encryption key is freely generated by the user. No one can decrypt the data except the user himself. And it realizes the data exchange of multiple cloud platforms based on Cloud 5 technology, which helps enterprises or individuals to protect and manage data. When there are any problems, immediately click to restore, you can restore the original data, so that 'full of blood resurrection'.

Backup needs to pay attention to the following points: the amount of data backed up; the speed and reliability of backup and recovery; the convenience of backup and recovery operation. In order to reduce the amount of backup data and speed up backup and recovery, a comprehensive backup, recovery and archiving strategy and a new generation of deduplicated backup technology can be adopted. Among them, comprehensive backup, recovery and archiving archives the inactive and final form of data to reduce the size of production data, which reduces the amount of data backed up, the recovery time is shorter, and the performance is more stable. and can realize the advantage of hierarchical storage.

The recovery mechanism of any backup technology requires a process opposite to the backup process, which usually takes a long time. If the user requires a high recovery time of RTO, it is difficult to use tape backup. In order to meet the requirements, disk backup must be used.

Local replication and remote replication technologies make a copy of the source data, which can not only provide near-immediate recovery, but also be used for non-disruptive backup, decision support, application testing and development, third-party software updates, etc.; their purpose is to ensure the "linearity" of system data and services, that is, when the system fails, it can still provide data and services to restore the system to normal.

2. Local replication

Local replication includes snapshots and clones. A snapshot is an image of data at a certain point in time (the point in time at which the copy begins). It is a pointer-based, space-saving logical copy that usually requires less than 30% of the source volume capacity and is fast. A clone is a complete copy of the data, a real copy, its process is slow, and each copy requires the same storage space as the source volume.

3. Remote replication

Remote replication provides a strong guarantee for business continuity and disaster backup, ensuring the availability of data and systems through remote site failover, and the data can be restored and the business continues to operate within minutes of downtime in the production center.

Remote replication includes synchronous and asynchronous remote mirrors. Synchronous remote mirroring means that local data is copied to different places in a completely synchronous way through remote mirroring software. Every local Imax O transaction needs to wait for the confirmation of the completion of the remote replication before it is released. Asynchronous remote mirroring ensures that the basic Imax O operation to the local storage system is completed before updating the remote storage system, while the confirmation information provided by the local storage system to the requesting mirror host is completed, and the remote data replication is carried out synchronously in the background.

4. Real-time continuous replication

Continuous data protection (CDP, Continuous Data Protection), its key word is persistence. For a given dataset, CDP provides a continuum of recovery points that can access data at any point in time, not just for specific moments predetermined by the snapshot process. CDP allows applications to revert to a specific point in time rather than to a predetermined point in time. Recovery points are selected and dynamically rebuilt after time occurs. It provides unlimited granularity of recovery points (RPO).

5. How to achieve the fastest recovery and minimum loss?

In a state of mind, I hope that RTO=0,RPO=0, that is, the disaster has no impact on enterprise production, will not lead to production standstill, nor will it lead to the loss of production data. But obviously this is not realistic, it is a utopian dream. What the enterprise should do is to minimize the loss caused by the disaster.

The shorter the RTO time, it means that you are required to return to the usable state in less time. Although from a management perspective, the shorter the RTO time, the better, it also means more cost investment, that is, you may need to buy faster storage devices or high-availability software. For enterprises in different industries, their RTO goals are generally different. Even in the same industry, due to the different scale of business development, the RTO goals of different enterprises will be different. Therefore, when building a disaster recovery backup system, enterprises should first find the RTO target that is suitable for the enterprise itself, that is, under the definition of this goal, the investment for disaster backup should not be greater than the corresponding business loss.

Although enterprises have more or less different requirements for RPO/RTO, multi-backup believes that no matter whether enterprises have high requirements for RPO/RTO or not, backup / recovery can be used to build disaster recovery systems. However, the traditional backup software has great limitations in this respect, the main reason is that the management of multiple copies is not perfect. Multi-backup under Shenzhen Mulang Technology is a product that integrates the functions of managing and protecting user data. Data can be uploaded to the cloud in a few simple steps, and the data can be managed and protected in the cloud. At the same time, multiple backups can also achieve data interoperability between multiple clouds, minimizing the risk of data loss. And allow recovery to any file version, providing real-time, reliable and continuous protection for the data. It can be said to be the best choice for backup and disaster recovery.

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