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Backup Strategy

4 Types of Incremental Backup and Critical Best Practices

What Is Incremental Backup?

Incremental backup strategy involves creating copies of data that has changed since the last backup operation occurred. You can employ an incremental backup process to document changes in your data. Ideally, a backup system should package your incremental backup copies together to provide a full backup.

For example, you can run a full backup on Monday and set up the system to perform incremental backups on Tuesdays, Wednesdays, and Thursdays. Each incremental backup includes only changes made during the previous business day. In this scenario, if even one incremental copy is missing, the system cannot provide a full data record.

In this article:

Incremental Backup Types

Here are types of incremental backups, including scenarios for fully backing up or updating data:

1. Synthetic Full Backup

A full backup requires copying and reading data from a primary store. To create a synthetic full backup, the system reads the last full backup and any incremental backups following.

Traditionally, backup administration used the time window between the end of a workday and the next morning to complete all backups. Currently, many organizations conduct round-the-clock operations or manage business internationally, which has eliminated the backup window. There is often insufficient time to conduct a full backup without interrupting business processes.

Many organizations also have vast data stores, so full backups are not feasible. Synthetic full backup helps reduce the need to conduct a traditional full backup.

2. Incremental Forever Backup

With an incremental forever backup, only one initial full backup is created, and then following incremental backups are transferred to a centralized backup system. When the client needs to restore from backup, a full backup is generated on-the-fly and transferred from the backup system to the client.

The system achieves this by sending each incremental backup to disk or cloud storage. It breaks data into chunks and saves it to the backup destination. The system stores metadata about the chunks in a persistent system, creating a point-in-time backup that maps to the data chunks that make up that backup.

3. Enhanced Incremental Backup

Some backup vendors have a feature called enhanced incremental backup. This feature provides additional monitoring functionality to help ensure that each backup is comprehensive and current.

In an enhanced incremental backup, the system can identify files that were renamed or moved. This can improve efficiency when backing up large files.

4. Reverse Incremental Backup

Reverse incremental backups are similar to the synthetic full backup approach. The process starts with a full backup. The system creates an initial incremental backup and applies to the original full backup to create a new copy of the full backup. This process occurs without modifying the first full backup.

The system prepares the next incremental backup by identifying changes compared to the current full backup. These changes are used to create another, more current full backup. In this way, you always have access to a full backup copy. This means it is possible to return to a previous full copy to handle events like ransomware or data loss.

Related content: Read our guide to backup strategy

Incremental vs Differential Backup

The incremental and differential backup approaches are two ways to ensure that each backup only affects the data changed since the previous backup.

Differential backups
Differential backups archive any files modified after the latest full backup.

For instance, you perform a full backup on Monday. On Tuesday, you back up the files modified after Monday, and on Wednesday, you back up the files modified after Monday. This process continues until you conduct your next full backup.

Here are some differences between full backups and differential backups:

  • Differential backups are faster than full backups—you are backing up less volume of data, however, the volume of data you are backing up increases with each differential backup until you carry out the next full backup.
  • Differential backups provide greater flexibility than full backups—however, they still take time and cannot be carried out very frequently unless large amounts of storage space are available.

Incremental backups
Incremental backups back up any changed data, however, you only back up the files modified since the most recent backup—irrespective of whether it was a full or incremental backup. That is why they are sometimes known as "differential incremental backups”.

For instance, if you conduct an incremental backup on Wednesday, you only backup the files modified after the incremental backup performed on Tuesday. This approach creates a faster, smaller backup, meaning the shorter the interval between each backup, the smaller the amount of data you need to backup.

Incremental backups provide improved granularity and flexibility. However, they can take longer to restore. The restoration process is lengthy because you must reconstruct the backup from the last full backup and every incremental backup that came after.

Learn more in our details guide to incremental vs. differential backup

Incremental Backup Best Practices

Maximize the Recovery Server’s Processing Power

When using incremental backups for recovery, the process needs to merge a significant number of files. This compute-intensive process often takes a long time and slows down recovery. You can mitigate this issue by prioritizing the backup processes on the server to achieve a faster recovery time.

Combine Multiple Backup Approaches

A hybrid approach can help you make the most of different backup strategies. For example, you can execute a full backup process throughout the weekend and run your incremental backups during the week.

Vary Your Incremental Backup Granularity Levels

Backup vendors provide various levels of granularity for your incremental backups. Here are the smallest units that most vendors can backup when changes occur:

  • File-level—creates an incremental backup for any file that has changed. This option is ideal for small files, such as office documents. However, it is less efficient for large files, such as databases.
  • Block-level—creates an incremental backup for any block within a single file. The process runs for blocks that have changed. This option provides fast results and uses less storage space than if you attempt to back up an entire file. However, not all backup providers support block-level management, and support may depend on integration with your file system or storage area network (SAN).
  • Byte-level – creates an incremental backup for any individual byte of data that has changed. This option offers the smallest possible incremental backups, allowing you to easily transmit and store them. However, this can lead to excessive processing overhead in your backup server.

Incremental Backup with NetApp Cloud Backup

NetApp understands ONTAP better than anyone else, which is why the best backup solution for ONTAP systems is NetApp Cloud Backup. Designed by NetApp specifically for ONTAP, Cloud Backup automatically creates block-level incremental forever backups. These copies are stored in object format and preserve all ONTAP’s storage efficiencies. Your backups are 100X faster to create, easy to restore, and much more reliable than with any other solution.

Cloud Backup simplifies the entire backup process. It’s intuitive, quick to deploy, and managed from the same console as the rest of the NetApp cloud ecosystem. Whether you’re looking for a less expensive way to store your backups, a faster, more capable technology than NDMP, or an easy way to enable a 3-2-1 strategy, Cloud Backup offers the best backup solution for ONTAP.

Learn more about NetApp Native Backup in the Cloud, Designed for ONTAP, and find out more in our Cloud Backup Service Customers’ Case Studies

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Semion Mazor, Product Evangelist

Product Evangelist