Do I need RAID if I have backup?

What is RAID?

RAID (Redundant Array of Independent Disks) is a data storage technology that combines multiple disk drives into a logical unit for redundancy and/or performance purposes https://www.techtarget.com/searchstorage/definition/RAID.

There are different RAID levels that provide varying levels of redundancy and performance:

  • RAID 0 stripes data across multiple drives for improved performance, but does not provide redundancy.
  • RAID 1 mirrors data across drives for redundancy, but does not improve performance.
  • RAID 5 stripes data and parity information across drives, providing redundancy while improving performance.
  • RAID 6 is similar to RAID 5 but stripes dual parity for higher fault tolerance.
  • RAID 10 combines mirroring and striping for both redundancy and performance.

The redundant nature of most RAID levels allows continued access to data in the event of a single or sometimes multiple drive failures. RAID aims to provide increased storage reliability and/or performance https://en.wikipedia.org/wiki/RAID.

Benefits of RAID

RAID offers several key benefits compared to single hard drives:

Increased read/write performance – By spreading data across multiple drives, RAID can increase bandwidth for reading and writing data. This is achieved through disk striping, which interleaves data across the drives. For example, RAID 0 provides performance improvements by striping data without redundancy.

According to TechTarget, disk striping in RAID “improves performance by allowing input/output (I/O) operations to overlap in a balanced way.”

Redundancy against drive failures – Many RAID levels offer protection against drive failures by creating redundant copies of data across multiple disks. If one disk fails, data can still be read from the remaining disks. For example, RAID 1 mirrors data between two drives while RAID 5 uses parity to recover data if a single drive fails.

Different RAID levels optimize for speed, redundancy, or both – There are various standardized RAID levels (RAID 0, 1, 5, 6, etc) that prioritize performance, redundancy, or a balance. For instance, RAID 0 focuses solely on performance while RAID 1 optimizes for redundancy at the cost of usable disk space.

According to DiskInternals, “The type of RAID level defines its fault-tolerance and performance, as each one provides a balance between these two parameters.”

What is Backup?

Backup refers to the process of creating copies of data to enable recovery in case the original data is lost or corrupted. Backup protects against data loss by storing extra copies of data in a different location than the primary data storage. There are different types of backup:

  • Full backup – Copies all the data files and folders to the backup destination.
  • Incremental backup – Copies only the data that has changed since the last backup.
  • Differential backup – Copies all the data that has changed since the last full backup.

Backups can be stored locally, like on an external hard drive, or remotely in the cloud. Local backups provide faster restore times but are at risk if the same physical location is damaged. Offsite cloud backups provide protection if the primary location is affected by disaster like fires, flooding, etc.

Cloud-based backup services like Cloudian Hyperstore provide benefits like automated scheduling, unlimited scalability, and geographic redundancy across multiple data centers.

Benefits of Backup

Backing up data provides several key benefits that help prevent data loss and ensure the ability to recover critical information when needed. Some of the main advantages of performing regular backups include:

Protects against data loss from drive failures – Backups provide protection if a hard drive or storage device fails. Having a backup ensures the data can be restored to a new drive if the original becomes corrupted or stops working. This guards against permanent loss of data due to hardware issues.

Allows recovery of deleted or corrupted files – Even if a file is accidentally deleted or becomes corrupted, a backup provides a way to retrieve the previous version of that file. This helps recover from errors or mishaps that may otherwise cause irrecoverable data loss.

Provides offsite protection against disaster – Storing backups remotely in the cloud or at an offsite location defends against catastrophic events like fires, floods, or ransomware attacks that could damage onsite data. Offsite backups ensure business continuity if a disaster strikes the primary location.

Sources:
https://www.netapp.com/cyber-resilience/data-protection/data-backup-recovery/what-is-backup-recovery/
https://www.bocasay.com/importance-data-back-up/

Differences Between RAID and Backup

The key differences between RAID and backup are:

RAID provides redundancy by spreading data across multiple disks, but backup captures copies of data to facilitate recovery after data loss. RAID protects against drive failures by reconstructing data from the remaining disks, but backup allows you to restore previous versions or copies of your data from a separate destination. So while RAID focuses on availability and performance through redundancy, backup aims to improve recoverability. According to TechTarget, “the main difference between RAID vs. backup is that, although backups help you recover from a data loss event, RAID exists as a tool for keeping systems and data continuously available” (TechTarget).

RAID safeguards against physical disk failures and keeps data continuously accessible on your server or computer through striping and mirroring. But backup creates copies of your data on external media to protect against a wider range of failures like system crashes, accidental deletion, data corruption, natural disasters, or cyber attacks. Backups are not designed to improve performance or availability like RAID.

By duplicating data across disks, RAID can enhance read/write speeds, input/output throughput, and processing power beyond single disks. But backup targets disaster recovery and does not provide performance gains.

Scenarios Where RAID Alone is Not Enough

While RAID provides redundancy in case of drive failure, it does not protect against all scenarios that can lead to data loss. Here are some situations where relying on RAID alone is not enough:

Complete system failure – If there is a catastrophic failure that affects the entire RAID system, such as a fire, flood or power surge, the entire RAID array can be destroyed. RAID only provides redundancy within the array itself (Creating Mirror (RAID 1) on Windows 10 causes not …,” n.d.). Having an external backup is essential for protection against complete system failure.

Theft of equipment – If the physical RAID system is stolen, the data will be lost unless there is an offsite backup. RAID does not help in this scenario.

Accidental deletion of files – If a file is accidentally deleted or overwritten, the deletion is instantly replicated across the RAID system. There is no protection against human error. A backup provides a way to recover deleted files.

Ransomware attack – If ransomware infects the system and encrypts the files, this encryption will spread rapidly across a RAID array. Backups provide the ability to roll back to an earlier unaffected version (“RAID is shit – why? : r/DataHoarder,” n.d.).

In summary, RAID only provides protection against drive failures within the array itself. To guard against catastrophic system failure, theft, accidental deletion, malware and other scenarios, an additional backup solution is highly recommended.

Scenarios Where Backup Alone is Not Enough

There are certain scenarios where relying solely on backup is insufficient from a data protection standpoint. Some key scenarios where backup alone falls short include:

Large scale drive failure – With large arrays of hard drives, the likelihood of multiple simultaneous drive failures increases. Backup alone cannot help recover quickly from multiple failed drives. RAID allows for continued operations and quick rebuilding in the event of multiple drive failures.

Need fast rebuild after drive failure – When a drive fails in a RAID array, the array can instantly start rebuilding onto a replacement drive using parity data. With only backup, you would need to completely restore from backup which takes much longer. As this Cisco article discusses, “RAID rebuilds data faster than restoring from backup”.

Seeking better read/write performance – RAID 0 can significantly improve read and write speeds by striping data across multiple disks with no parity. Backup does not provide any read or write performance gains.

Recommended Best Practices

To ensure comprehensive protection for your data, it is recommended to use both RAID and regular backups. RAID provides redundancy in case of drive failures, while backup protects against data loss from disasters, human error, ransomware, and more. Here are some best practices:

Use RAID 1, 5, 6, 10, or 50 depending on your performance and redundancy needs. RAID 1 and 10 offer the best performance, while RAID 5 and 6 provide better storage efficiency. Determine how many drive failures you want to protect against.

Implement both onsite and offsite backups. Onsite backups to an external drive protect against local failures, while offsite cloud backups guard against site disasters like fires or floods. The 3-2-1 backup rule recommends maintaining 3 copies of data, on 2 different media, with 1 copy offsite.

Test restores regularly to validate your backups. Backup software usually includes options to perform test restores.

Use drive/system cloning and imaging for quick disaster recovery. Apps like Macrium Reflect facilitate disk imaging for fast system restores.

Follow the best practices of your backup software for versioning and retention. Most backup software deletes old backups after a set time period.

Encrypt and password-protect backups to guard against unauthorized access.

By leveraging both RAID and comprehensive backup procedures, you can achieve reliable protection for your important data. RAID safeguards against drive issues while backup shields against a wide array of threats.[1] [2]

Sample RAID and Backup Configurations

Here are some recommended RAID and backup configurations for different use cases:

Home Media Server

For a home media server storing movies, music, and photos, a RAID 1 configuration provides redundancy in case of a drive failure. Pair this with an external hard drive to periodically create backups of the media files (Prepressure). The external drive can be stored offsite for protection against theft or natural disaster.

Business Database Server

For a business database server storing critical company data, a RAID 10 configuration provides high performance and redundancy. Additionally, set up hourly incremental backups to a NAS device along with daily full backups to an external hard drive stored offsite (Wikipedia). This ensures both high availability and multiple backup points in case data needs to be restored.

Personal Computer

For a personal home computer, pairing a small SSD system drive in a RAID 0 configuration for speed with a larger HDD data drive provides good performance and storage capacity. An online backup service like Backblaze provides offsite cloud backups in case the computer is damaged, stolen, or there is a local disaster (Intego).

Conclusion

In summary, RAID and backup serve complementary purposes. RAID provides improved performance, availability, and recoverability in the event of drive failures. Backup creates restorable point-in-time copies of data to protect against catastrophic failures, accidental deletion, corruption, or disaster.

While RAID and backup offer overlapping benefits, one cannot completely replace the other. RAID suffers from the risk of controller failure, stripe corruption, or user error destroying the RAID array. Backup carries the risk of incomplete backups, media failure, or outdated recovery points.

To ensure maximum protection and performance, it is best to implement both RAID and regular backups. RAID safeguards availability and recoverability for hardware failures. Backup protects against data loss scenarios that RAID cannot address. Together they provide defense-in-depth for valuable data. The specific RAID level and backup methodology can be tailored to balance performance, cost, and data protection requirements.