There are some key differences between clones and backups that are important to understand. At a high level, a clone is an exact copy of data at a point in time, while a backup is a copy of data that can be updated and restored over time.
What is a clone?
A clone is an identical copy of data from a source. When cloning, the entire contents of a source are copied bit-for-bit to create the clone. Some key characteristics of clones:
- Clones contain an exact replica of data from the source at a specific point in time.
- Making changes to the clone does not affect the original source.
- Clones require the same or greater amount of storage space as the source.
- Cloning copies everything, including the operating system, applications, and configurations.
- Common uses of cloning include duplicating hard drives, creating new virtual machine instances, and replicating production environments for testing.
In summary, a clone provides an identical snapshot of the source data. The clone is isolated from the original source, allowing changes to be made without affecting the source. Cloning requires sufficient storage for the complete copy and is focused on duplicating the environment at a point in time.
What is a backup?
A backup is a copy of data that is intended for recovery purposes in case the original source is lost or corrupted. Backups are different from clones in several key ways:
- Backups capture copies of data over time, allowing different versions to be restored.
- Backups only contain the changed data since the last backup, minimizing storage requirements.
- Backups do not produce a usable duplicate version of the source system.
- The backup does not need to be a complete copy of the source data.
- Common uses of backups include recovering deleted or corrupt files and restoring data in disaster scenarios.
In summary, backups provide a way to restore data to a previous state if needed. Backups only contain incremental changes over time rather than complete duplications. The tradeoffs are that backups require less storage but do not allow instantly spinning up a cloned environment.
Key differences between clones and backups
Here is a summary of the key differences between clones and backups:
| Clone | Backup |
|---|---|
| Exact copy of source at a point in time | Copy of changed data over time |
| Complete duplicate environment | Selective data recovery |
| Isolated from source | Dependent on source data |
| Significant storage space needed | Minimized storage requirements |
| Used for duplicating environments | Used for recovery and restoration |
As this comparison shows, clones and backups serve different purposes. Clones produce standalone duplicates, while backups capture history for data recovery.
Common cloning scenarios
Here are some common scenarios where clones are used:
- Creating replica test environments – Clones allow production environments to be replicated in a test or QA environment to ensure updates and configurations are thoroughly tested before deploying to production.
- Duplicating virtual machine instances – Virtual machine (VM) clones provide quick deployment of additional identical VMs by cloning a configured VM image or snapshot.
- Migrating data to new storage – Cloning can migrate data to new storage systems by cloning to the new storage then redirecting users to the clone.
- Replacing a failed hard drive – Cloning a drive allows it to be replaced with an identical copy to minimize system downtime.
In these examples, clones allow fully functional duplicates to be created quickly from a source. The clones can then be used for testing or replacement purposes.
Common backup scenarios
Here are some common scenarios where backups are used:
- Recovering from data corruption or deletion – Backups provide the ability to restore previous correctly functioning versions of data in case of corruption or accidental deletion.
- Disaster recovery – Backups are critical for recovering from disasters like hardware failure, ransomware, fires or natural disasters. Systems can be restored from backups.
- Compliance and retention – Regulated industries often have data retention requirements that can be met by retaining backups for specified time periods.
- Long-term archival – Historical backups allow accessing and restoring older versions of data when needed long after the originals are deleted or altered.
Backups are focused on data recovery use cases rather than duplicating environments. The ability to restore previous versions of data from backup is essential for mitigating data loss risks.
Should you clone or backup?
Whether to use cloning or backup depends on the specific objectives:
- For quickly duplicating known good environments at a point in time, cloning is preferable.
- For protecting against data loss and restoring previous versions, backup is preferable.
- For deploying multiple copies of environments like testing and development, cloning is typically faster.
- For minimizing storage space requirements, backup is more efficient.
- For compliance and data retention needs, backups are usually required.
- For replacing failed hardware, cloning simplifies replacement with an identical copy.
In most cases, a combined clone and backup strategy is advisable. Cloning provides duplicates for use cases like testing and redundancy. Backup provides the history to restore previous data versions as needed.
How clones work technically
On a technical level, a clone operation copies data from a source to a destination location. The exact process depends on the storage infrastructure:
- Block storage cloning – Block-level clones make an identical copy of disk volumes by duplicating blocks of data from the source volume to the clone. No higher-level file system information is needed.
- File-level cloning – For file or application-level cloning, the file system metadata is duplicated in addition to copying file contents. This preserves permissions, ownership, timestamps, etc.
- Application-consistent cloning – Application clones combine file-system and block cloning with application-specific consistency techniques like snapshots or suspend/resume to clone active applications consistently.
Cloud computing, virtualization, and data deduplication technologies have made cloning much more efficient and space-saving compared to traditional full file copies. However, care must still be taken to ensure consistency when cloning at the application level.
How backups work technically
There are several core technical methods used for performing backups:
- Full backups – A full backup copies all the data selected for backup each time the backup runs. This provides a complete restore ability but takes more storage space.
- Incremental backups – Incremental backups only copy data changed since the most recent backup, saving significant storage space compared to full backups.
- Differential backups – Differential backups save all changes since the last full backup, requiring less administration than incremental backups.
- Snapshot backups – Snapshots capture the state of data at a point in time without directly backing up the data. Storing snapshots requires less space than full copies.
Backup systems combine these approaches to balance recovery ability against storage space. Common strategies include full weekly backups combined with daily incrementals or differentials.
Considerations when cloning or backing up
Key considerations when planning a cloning or backup strategy include:
- Available storage space – Cloning requires enough free space to hold full duplicates, while backup space depends on the strategy.
- Acceptable restore time – Backups require time to recover, while clones can instantly provide a duplicate environment.
- Network capacity – Cloning and backups both place demands on network bandwidth for data transfers.
- Change rate – High change rates can impact backup windows and sizes. Source size changes less often affect cloning.
- Security and compliance – Cloning and backup systems must meet security and compliance standards for managing and storing copies.
Understanding details like required recovery times, available bandwidth, data change frequency, and regulatory compliance helps determine appropriate cloning and backup solutions.
Conclusion
In summary, clones and backups serve complementary purposes. Cloning produces identical environmental copies at a point in time, while backups capture historical data changes for recovery needs. Typical best practices are:
- Use cloning for speeding up deployment of duplicate known good environments.
- Use backup for restoring previous versions and protection against data loss.
- Combine cloning and backup together for comprehensive copy management.
Both cloning and backup provide business continuity and efficiency benefits. The optimal solution chooses the right technologies for the specific technical and business objectives.
