Class 10 | Database Backup, Recovery and Security | DBMS Notes

Backup:
Backup refers to the process of creating duplicate copies of data to safeguard it against loss, corruption, or accidental deletion. It is an essential part of data management and disaster recovery planning.
Types of Backup:
i) Physical Backup: Physical backups involve copying data at the storage level, typically at the block or disk level. This type of backup captures the entire contents of the storage device, including the operating system, applications, and data files.

Characteristics of Physical Backup:

i)  Capture data at the storage level, typically at the block or disk level.
ii) Include the entire contents of the storage device, including the operating system, applications, and data files.
iii) Can be resource-intensive in terms of storage space and backup duration.
iv) Types include Full Backup, Incremental Backup, and Differential Backup.
v) Suitable for disaster recovery scenarios where the entire system needs to be restored quickly.
vi) Requires specialized backup software and hardware for efficient management.
vii) May involve downtime during backup operations, especially for full backups.
viii) Ideal for environments where the underlying storage architecture is homogeneous and well-defined.

  1. ii) Logical Backup: Logical backups involve copying data at a higher level of abstraction, such as databases, files, or directories. Unlike physical backups, which copy data at the storage level, logical backups capture data in a format that is independent of the underlying storage architecture. Logical backups are often used for specific types of data, such as databases or files, and can be more flexible than physical backups.

    Characteristics of Logical Backup:
    i)
    Capture data at a higher level of abstraction, such as databases, files, or directories.
    ii) Independent of the underlying storage architecture and capture data in a format that is easily accessible and portable.
    iii) Types include Database Backup, File-Level Backup, and Application-Level Backup.
    iv) Provide flexibility in selecting specific data sets for backup and recovery.
    v) Require application-specific backup tools or utilities to capture data efficiently.
    vi) Can be more granular in terms of backup and recovery, allowing for selective restoration of individual files or
    vii) Suitable for environments with diverse data sources and applications.
    viii) May require additional processing overhead during backup operations, especially for application-level backups that involve database dumps or file exports.

Advantages of Database Backup, Recovery & Security:
i) Data Security:
Database backups serve as a crucial component of data security measures. They ensure that in the event of data loss due to system failures, human error, or cyber-attacks, organizations can restore their databases to a known, secure state. By implementing robust backup strategies, including encryption and access controls, organizations can safeguard sensitive data against unauthorized access and data breaches.

ii) Data Recovery and Replication:
Database backups facilitate quick and reliable data recovery. In the event of data corruption, accidental deletion, or system failures, organizations can restore databases from backup copies, minimizing downtime and preserving business continuity. Database replication, which involves creating and maintaining redundant copies of databases across multiple locations, enhances data resilience and availability. Replication ensures that organizations can continue operations even in the face of localized outages or disasters.

iii)Easy Data Management:
Database backups simplify data management by providing a centralized repository for storing and organizing data copies. Administrators can schedule automated backup tasks, manage retention policies, and monitor backup operations from a single interface, streamlining administrative overhead.

iv) Cost Control:

Effective database backup strategies can help organizations control costs associated with data loss and downtime. By investing in backup infrastructure and implementing efficient backup processes, organizations can mitigate the financial impact of data-related incidents and avoid costly disruptions to operations.

v) Unhindered Performance:

Modern backup solutions offer capabilities such as incremental backups, snapshot-based backups, and parallel processing, minimizing the impact on production systems during backup operations. By reducing backup windows and resource consumption, organizations can ensure optimal performance of critical databases and applications.

vi)Increased Competitive Advantage:

Reliable database backup and recovery capabilities contribute to organizational resilience and agility, giving businesses a competitive edge. By demonstrating a commitment to data protection and continuity, organizations can enhance customer trust, comply with regulatory requirements, and differentiate themselves in the marketplace.

vii)Maintaining Standards or Compliance:

Database backups play a crucial role in meeting industry standards and regulatory requirements related to data protection and retention. Organizations subject to regulations such as GDPR, HIPAA, or PCI DSS must implement robust backup and recovery processes to ensure compliance and avoid penalties. Regular database backups provide auditable records of data changes and transactions, supporting compliance efforts and regulatory reporting obligations.

Challenges of Database Backup, Recovery and Security with Strategy
i) Scheduling Backup Regularly:
Challenge: Ensuring that database backups are scheduled and executed regularly can be challenging, especially in environments with complex data architectures, multiple databases, and distributed systems.
Strategy: Implement automated backup scheduling tools and practices to ensure consistent and timely backups. Use backup software with scheduling capabilities to automate backup tasks according to predefined policies and schedules. Regularly review and update backup schedules to accommodate changes in data volumes, usage patterns, and business requirements.

ii) Preventing Data Corruption:
Challenge: Data corruption can occur due to various factors, including hardware failures, software bugs, human errors, and malware attacks. Corruption can render backups unusable and compromise data integrity.
Strategy: Employ data validation techniques such as checksums, data integrity checks, and consistency checks to detect and prevent data corruption. Implement redundancy and fault-tolerant storage solutions to minimize the impact of hardware failures. Regularly test backup and recovery processes to ensure data recoverability and integrity.
ii) Aligning with Your Architecture:
Challenge: Database backup and recovery processes must align with the organization’s data architecture, including the types of databases used, data storage solutions, and IT infrastructure.
Strategy: Tailor backup strategies and technologies to suit the specific requirements of your data architecture. Choose backup solutions that support diverse database platforms and storage environments. Consider factors such as scalability, performance, and compatibility when selecting backup tools and technologies.

iv) Setting Data Backup Priorities:
Challenge: Not all data is equally critical, and organizations may struggle to prioritize backups for different types of data and applications.
Strategy: Conduct a comprehensive risk assessment to identify and prioritize critical data and applications based on factors such as business impact, regulatory requirements, and recovery objectives. Define backup policies and service-level agreements (SLAs) that align with the importance and sensitivity of different data sets. Allocate resources and investments accordingly to ensure adequate protection for high-priority data.
v) Protecting Against Ransomware:
Challenge: Ransomware attacks pose a significant threat to data security and availability, as they can encrypt or delete critical data and backups, rendering them inaccessible.
Strategy: Implement multi-layered security measures to protect against ransomware attacks, including endpoint protection, network security, access controls, and user education. Maintain offline backups stored in secure, isolated environments to prevent them from being compromised by ransomware. Regularly test backup and recovery processes to ensure readiness to respond to ransomware incidents.

Methods of Backup:

i) Full Backup: A full backup involves copying all data from the source to the backup destination. It provides a complete snapshot of the data at a specific point in time. Full backups are comprehensive but can be time-consuming and require significant storage space. Ideal for creating a baseline backup or restoring entire systems in case of data loss.

ii) Incremental Backup:
Incremental backups capture only the changes made since the last backup, whether it was a full backup or an incremental backup. This approach saves time and storage space compared to full backups but requires a sequence of backups to restore the data completely. To restore data from an incremental backup, you need the last full backup and all subsequent incremental backups.

iii) Differential Backup
: Differential backups capture all changes made since the last full backup. Unlike incremental backups, which only capture changes since the last backup (whether full or incremental), differential backups capture changes since the last full backup. This means that each differential backup contains all changes made since the last full backup, making it easier to restore data compared to incremental backups.

iv) Mirror Backup
: Mirror backup creates an exact copy of the source data without any compression or encryption. It mirrors the source data to the backup destination, essentially creating a replica. Mirror backups are useful for creating redundant copies of critical data for disaster recovery purposes.

v) Full PC Backup:
Full PC backup involves creating a complete backup of an entire computer system, including the operating system, applications, settings, and data files. It enables the restoration of the entire system to a previous state in case of system failures, hardware crashes, or other disasters.

vi) Local Backup:
Local backup involves storing backup copies of data on storage devices that are physically located in the same premises as the source system. Common local backup solutions include external hard drives, network-attached storage (NAS), or tape drives.

vii) Offsite Backup:
Offsite backup involves storing backup copies of data at a remote location, separate from the source system. This provides protection against localized disasters such as fires, floods, or theft. Offsite backup solutions may include transporting physical backup media to a remote location or using cloud storage services.Online Backup: Online backup, also known as cloud backup, involves storing backup copies of data on remote servers accessed via the internet. It offers scalability, accessibility, and reliability, making it an ideal solution for organizations of all sizes. Online backup services typically offer features such as automated backups, encryption, and versioning.

viii) Remote Backup:
Remote backup refers to storing backup copies of data on remote servers accessed over a network connection. It can include both local and offsite backup solutions, depending on the location of the remote servers. Remote backup enables data protection and disaster recovery without the need for physical proximity to the backup destination.

ix) Cloud Backup
: Cloud backup, involves storing backup copies of data on remote servers accessed via the internet (online backup). It offers advantages such as scalability, flexibility, and cost-effectiveness compared to traditional backup solutions. Cloud backup services often include features such as automated backups, encryption, de-duplication, and data retention policies.

x) FTP Backup:
FTP (File Transfer Protocol) backup involves transferring backup copies of data to a remote server using the FTP protocol. It provides a simple and straightforward method for transferring files over a network connection. FTP backup can be used for both local and offsite backup scenarios, depending on the location of the FTP server and backup destination.
Reasons of Database Failure

Failure in terms of database can be defined as the inability of database to execute the specified transaction or loss of data from the database. A DBMS if vulnerable to several kinds of failures and each of these failures needs to be managed differently.

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