Ⅰ. Backup Technology
Ⅱ. Backup system
Ⅲ. Avoid failure and damage of backup storage media
Ⅳ. What are the common problems that may be encountered during the backup process?
Ⅴ. How to test the recoverability and integrity of backup data?
Ⅵ. What is backup frequency? How do I determine the appropriate backup frequency?
Backup is the basis of disaster recovery. It refers to the process of copying all or part of the data set from the hard disk or array of the application host to other storage media in order to prevent data loss caused by system operation errors or system failures. Traditional data backup mainly uses built-in or external tape drives for cold backup. But this method can only prevent man-made failures such as operating errors, and its recovery time is also very long.
With the continuous development of technology and the massive increase of data, many enterprises have begun to use network backup. Network backup is generally realized through professional data storage management software combined with corresponding hardware and storage devices.
Ⅰ. Backup Technology
1. System Disaster Recovery
System disaster recovery means that when the system crashes, the system can be rebuilt with very few steps, including the above system patches, application software and data. This improves recovery accuracy, shortens recovery time, and reduces business interruption time.
There are several ways to restore the main disaster recovery technology:
(1) It is necessary to carve a CD for each computer separately. When restoring, you need to use a specific CD to restore. Each machine needs its own CD, and it needs to be updated regularly. The biggest disadvantage of this method is that it is often necessary to engrave a CD, otherwise, if there is no CD or the CD is too long when a disaster occurs, the speed of recovery and the restored state will be affected. A typical representative of this technology is the EMC NetWork Recovery Manager module.
(2) A common optical disc is adopted, and all systems adopt this optical disc. This CD can start the system, and can start the network at the same time, and then the backup server restores the entire hard disk content or the first primary partition content backed up in the tape library (or virtual tape library) to the disaster machine.
(3) When restoring, it needs to be started with the help of the network, that is, a host with the same operating system needs to be used as the boot machine, and then the backup content is used for restoration. A typical representative of this technology is Symantec NetBackup's Bare Metal Restore (Bare Metal Restore) module.
(4) Disaster recovery tools provided by the operating system itself. For most Unix minicomputers, system backup tools are provided. With the help of the tape drive provided by the system itself, using a simple command, HP-UX can use make_recovery to back up the entire root volume to the 4mm tape that comes with the server. When restoring, this tape can start the system automatically, and the entire root volume can be restored to the hard disk with a single command. The advantage of this method is that it is simple and economical. Especially for Unix systems, this method is far more convenient, safe and economical than the BMR module provided by the backup software, because the BMR module provided by the backup software often requires other servers of the same platform to start. The difference between backup and archiving and data synchronization
2. Data Protection Technology
Abbreviated as CDP, CDP technology is currently the most popular data protection technology. It can capture all data write changes at the file level or data block level, and can restore backup objects at a more granular level to any point in time.
CDP technology is an emerging technology, which is gradually integrated into many traditional backup software. For example, BakBone NetVault Backup 8.0 added the TrueCDP module, Symantec Backup Exec12.5 and so on.
CDP technologies include:
(1) TrueCDP, we call it true CDP, it can restore any point in time (APIT, Any Point In Time) within the specified time period, and BakBone TrueCDP belongs to the TrueCDP type.
(2) Near CDP is what we call quasi-CDP. Its biggest feature is that it can only recover part of the data at a specified point in time (FPIT, Fixed Point In Time). It is a bit similar to the logical snapshot of the storage system, and it cannot restore any one point in time. CDPs such as Symantec, CommVault, and Kay Backup all belong to this type.
3. Data remote replication
Generate a usable copy of the data in another place in real time. The use of this copy does not require data recovery, and the copy can be put into use immediately. The biggest benefit of data replication is that the replica data is immediately available and there is no data recovery time.
The disadvantage is that the cost is much higher than that of data backup, not only the high price of the data replication system, but also the need for additional hard disk storage space and host system, and even the establishment of another remote computer room.
Considering the network wiring, these will greatly increase the cost. Therefore, the construction and maintenance costs of data replication are far greater than data backup.
Data replication currently has the following implementation methods:
(1) Host-based. Host-based data replication technology does not need to consider the isomorphism of the storage system, as long as the hosts have the same operating system, there is data replication software that supports heterogeneous hosts, such as BakBone NetVault Replicator can support heterogeneous servers It can support remote real-time replication across the wide area network. The disadvantage is that it takes up a little host resources.
(2) Based on fiber optic switches. This technology is developing, using the new functions of the fiber switch, or using the management software to control the fiber switch to virtualize the storage system, and then the management software performs volume management, volume replication, volume mirroring and other technologies on the managed virtual storage pool, To achieve remote replication of data. The more typical ones are Storagerag-age, Falcon and so on.
(3) Based on the storage system. Using the data replication software provided by the storage system, the replicated data flow is transmitted between the storage systems, regardless of the host. The advantage of this method is that data replication does not occupy host resources. The disadvantage is that the storage system of the disaster recovery center and the storage system of the production center have strict compatibility requirements. Generally, storage systems from the same manufacturer are required. The selection of the storage system of the disaster recovery center brings restrictions.
(4) Application-based data replication. This technology has certain limitations, which are application-specific. It is mainly accomplished by using the replication modules provided by the database itself, such as OracleDataGuard, Sybase Replication, etc.
4. Application
BMR Bare Metal Recovery is adopted first, because this solution has the lowest cost, and it can be completed only by adding some modules when building the data backup system. No additional storage space or additional disaster recovery room is required, so almost all qualified users can implement it. It’s just that some users use the backup tool provided by the operating system to assist, and some users use the disaster module provided by the backup software to complete. The largest number of such users are distributed in various industries. BakBone's VaultDR is widely adopted by backup software users using BakBone NetVault.
Users who build disaster recovery systems and high-end enterprises with large data volumes generally use storage-based data replication technology, such as telecommunications and financial industries. Middle and low-end users generally use host-based data replication software, which is low in cost and does not require strict storage system purchases. In particular, BakBone's NetVault Replicator can not only perform remote data replication, but also support heterogeneous platforms. There are a wide range of users at home and abroad. Some government departments, power companies, securities departments, website companies, etc. all adopt this method, and most of them are used on Windows and Linux platforms.
Although the virtual storage technology based on the storage switch layer also has some users, because of the limited start-up time of this technology, the maturity of the technology needs to be further verified.
As for CDP technology, it has just started. This technology meets the needs of many users who care about disaster recovery. It can achieve high standards in terms of RTO and RPO. At the same time, it can reproduce any historical version. It is being increasingly The more users pay attention, I believe there will be a very wide range of users in the future.
BakBone's TrueCDP can be restored at any point in time. It is a real CDP. It will have greater advantages than other quasi-CDP products and will be chosen by more users who care about disaster recovery.
5. Mistakes in application
The disaster recovery system is considered omnipotent, the role of the disaster recovery system is exaggerated, and the construction of a backup system and a high-availability system is ignored. In fact, each system has its own role and needs to be built according to actual needs.
The selection of various disaster recovery technologies is unreasonable. For example, the resources of the host system can accept the host-based replication software to run, but the design based on the storage system is selected, resulting in the need to use the same type of storage device, which increases the overall cost.
For the disaster backup of the BMR system, it is always desirable to use the BMR module that comes with the backup software. In fact, the BMR module that comes with the backup software is more convenient for Windows and Linux, but it is not suitable for all Unix systems. In terms of Unix system backup, the system backup tools and tape drives that come with Unix are very convenient. One command can complete the system backup without depending on other servers, which is far better than the BMR module that comes with some backup software. It is not only easy to operate, but also reduces costs.
6. Future development direction
One of the future developments should be a wider market for host-based heterogeneous replication technology. Because most customers have a heterogeneous host environment and support the data replication technology of the heterogeneous environment, the existing environment can be used to replicate each other between hosts.
The second development in the future is CDP technology. CDP combines the advantages of data backup and data replication. It can not only protect real-time data, but also restore historical data at any point in time, and will have stronger vitality. With the seamless connection between TrueCDP and traditional backup software, more and more users will adopt TrueCDP for disaster recovery system construction.
Ⅱ. Backup system
1. Function of backup system
Data Recovery: The primary role of backup systems is to recover data in the event of data loss, corruption, accidental deletion, or catastrophic events. Through backup, the data can be restored to the previous state, ensuring that the business can continue to run and reduce business interruption.
Disaster Recovery Plan: Backup systems are a central component in a disaster recovery plan. In the event of natural disasters, fires, floods, etc., backups can help organizations recover affected systems and data quickly and mitigate the impact of the disaster.
Business Continuity: Backup systems help maintain business continuity. In the event of hardware failure, virus infection, ransomware attack, natural disaster, etc., backups can help organizations recover affected systems and data quickly and reduce downtime.
Prevent Data Loss: A backup system protects data from various risks such as hardware failure, malware, human error, etc. Even if something goes wrong with your data, you can still restore it from backup to avoid permanent data loss.
Test and Development: Backups can be used for test and development environments, ensuring that these environments are consistent with production environments, reducing errors and inconsistencies.
Reduce risk: the automation of backup reduces the risk caused by the operation of maintenance personnel.
Data migration and replication: The backup system can be used to migrate data between different hardware devices, operating systems or cloud platforms, so as to achieve smooth migration and replication of data.
2. Function of backup system
Expansion: The backup system can be easily expanded according to the needs of the application system.
Replication and creation of replicas: The main function of a backup system is to replicate data, creating a copy of the data for future restoration. These copies are usually kept on different storage devices or locations to ensure data security.
Regular backup schedule: The backup system allows administrators to set up regular backup schedules. Backups can be scheduled based on business needs and frequency of data changes to ensure backup data is always up to date.
Data compression and deduplication: Backup systems often support data compression and deduplication to reduce the space required for backup storage. This reduces storage costs and improves backup efficiency.
Incremental backup and differential backup: The backup system supports incremental backup and differential backup. Incremental backups only back up new or changed data since the last backup, while differential backups back up changes since the last full backup.
Data encryption: Backup systems can encrypt backup data to ensure the security of backup copies and prevent unauthorized access to backup data.
Monitoring and Reporting: Backup systems often provide monitoring and reporting capabilities to track the status and health of backup operations. Administrators can monitor backup success rates, storage utilization, and more.
Ⅲ. Avoid failure and damage of backup storage media
Choose reliable storage media: Choose high-quality, reliable storage media such as professional hard drives, tapes, solid-state drives, and more. Avoid low-quality, easily damaged storage devices.
Protect from physical damage: Avoid placing storage media where it is subject to physical shock, vibration, or pressure. Avoid dropping, crushing or bumping the storage media.
Regular inspection and maintenance: Regularly check the status of backup storage media to ensure there are no physical damage or hardware problems. If any problem is found, replace the damaged storage medium in time.
Power stability: Provide a stable power supply to avoid the impact of power fluctuations or power interruptions on storage media. Use a stable power supply such as a UPS (uninterruptible power supply) to protect the storage device.
Data Migration: Migrate backup data from one storage medium to another on a regular basis to prevent potential damage caused by a medium being continuously used for an extended period of time.
Data encryption: Encrypt backup data to protect the security of data on storage media. Even if the storage medium is stolen or lost, encrypted data cannot be easily accessed.
Environmental control: Make sure that the storage environment of the storage media meets the recommended temperature and humidity requirements. Avoid exposure to extreme temperatures, humidity, and dust to prevent damage to storage media.
Regular inspection and maintenance: Regularly check the status of backup storage media to ensure there are no physical damage or hardware problems. If any problem is found, replace the damaged storage medium in time.
Ⅳ. What are the common problems that may be encountered during the backup process?
Backup failure: The backup process may fail due to various reasons such as hardware failure, software error, insufficient storage space, etc. Failed backups can lead to an increased risk of data loss.
Data inconsistency: During the backup process, if the running application or database changes, the backup data may be inconsistent with the source data. This may affect the quality of data recovery.
Slow backup speed: The backup process may become slow due to network bandwidth, hardware performance, and other issues. Slow backups may extend the time window for backup operations and affect system performance.
Backup Conflicts: Backup conflicts can occur when multiple backup operations are running concurrently, leading to resource contention and backup instability.
Storage medium failure: The backup storage medium may be unreadable or lose data due to hardware failure, damage, aging and other reasons.
Backup Interruption: Interruption of the backup process may be caused by system crashes, power outages, network interruptions, etc., which may result in incomplete or irrecoverable backup data.
Data Integrity Issues: The integrity of backup data can be compromised by factors such as corruption, write errors, or data transmission errors. This may cause backup data to not be restored normally.
Recovery test issue: Although the backup data was successfully created, problems may occur during the actual recovery test. Test recovery is an important step in verifying the effectiveness of the backup system.
Ⅴ. How to test the recoverability and integrity of backup data?
Regular recovery test: Regular recovery test of backup data is an important method to verify whether the backup data is reliable. Select different backup recovery points, try to restore data from the backup, and ensure that the data can be restored normally, and the restored data is complete and correct.
Partial recovery test: Sometimes it may be necessary to recover only part of the data, such as restoring a certain folder or a specific type of file. Performing a partial recovery test can verify that the backup system can meet specific needs.
Encryption and compression testing: If the backup data is encrypted or compressed, make sure that the data can be decrypted and decompressed correctly during recovery testing. This avoids problems during the actual recovery.
Recovery test in different scenarios: Test backup data in different recovery scenarios, such as single file recovery, entire system recovery, database recovery, etc. This ensures that the backup system can successfully restore data under all circumstances.
Data verification and verification: Verify and verify the restored data after recovery to ensure that the restored data is consistent with the original data. Compare file hashes or signatures to verify data integrity.
Ⅵ. What is backup frequency? How do I determine the appropriate backup frequency?
The backup frequency refers to the interval at which the backup operation is performed, that is, how often the backup is performed. Determining the appropriate backup frequency is based on the importance of data, speed of change, business needs, and available backup resources.
Choose the appropriate backup frequency:
Data Importance: Consider the importance of data first. Critical and business data may require more frequent backups to ensure quick recovery in the event of failure or data corruption.
Velocity of change: Consider the rate of change of the data. If data changes frequently, backup frequency may need to be higher to capture the latest changes.
Recovery Point Objective (RPO): RPO refers to the acceptable level of data loss in the event of a failure. If the business requirement is to lose at most one hour of data in the event of a failure, then the backup frequency should be set to once per hour.
Backup resources: Consider available backup resources, including storage space, backup devices, network bandwidth, etc. If resources are limited, backup frequency may need to be determined based on resource availability.
