Data backups are a central component of IT security. The challenge is to make the process as efficient as possible and save storage space. Differential backup is one possible solution. Find out what advantages this method offers and how you can make better use of your company resources thanks to differential backups.
Definition: What is a differential backup?
A differential backup is a backup that includes only the data that has changed or been added since the last full backup. To restore a differential backup, you need the last full backup as well as the latest differential partial backup.
With differential backups, you can implement short backup cycles without requiring huge storage capacities. In addition to the full backup and the differential backup, there are also incremental backups. Often, all three variants are combined in an individual strategy for data backup.
Which methods of data backup exist
In order to understand what role differential backup plays in data protection, the other variants must also be briefly examined: full backup and incremental backup.
Variant 1: The full backup
With the full backup, all data is backed up completely. This makes the full backup the simplest method in terms of handling. This is because all data is backed up at a precisely determinable time and stored in a secure location.
For example, a full backup is created every evening. To import one of the backups later, you simply need the last full backup made.
Variant 1: Full backup
However, the full backup is also the most complex and therefore most expensive method of data backup. It consumes a lot of time to collect and store all data. In addition, for each individual backup you need storage capacity in the size of your entire data volume to be backed up.
Given the relatively high effort and resources required, some companies tend to perform backups too infrequently. In an emergency, often only outdated backups are then available. This is where methods such as differential and incremental backup come into play.
Variant 2: The differential backup
What makes full backups so costly is the fact that each backup stores countless data that rarely or never change. These are then present in multiple copies in each individual backup and occupy storage space.
This is where differential backup comes in. Here, only the data that has really changed or has been newly added is backed up. The basis for this is a full backup, which is made at the beginning. Each subsequent differential backup compares the current data status with this basis and backs up all data that has changed or is new.
For example, a full backup was made on Monday and a differential backup has been made every evening since then. On Friday morning there is a loss of data. To restore Thursday's backup, you need Monday's full backup and Thursday night's differential backup.
Variant 2: Differential backup
This way you can significantly reduce the amount of time and storage capacity needed. But there is a catch: the bigger the differences in the data, the bigger the differential backup will be. Over time, the storage capacity required becomes similar to that of a full backup. The only thing that helps against this is a new full backup as an updated starting point; or you can resort to an incremental backup.
Variant 3: The incremental backup
An incremental backup also saves only new or changed data. But there is a crucial difference to the differential method: the incremental backup does not use the last full backup as a basis, but the last partial backup made. If a data loss occurs, all incremental backups must be restored one after the other in addition to the last full backup.
An example: A full backup was made on Monday and an incremental backup has been made every evening since then. On Friday morning there is a data loss. To restore Thursday's backup, you need Monday's full backup and all incremental backups created up to and including Thursday evening.
This means that the incremental backup backups require the least storage space. The disadvantage is the great effort involved in restoring, because many different backup media have to be handled. This also increases the susceptibility to errors. Here, the differential method has a clear advantage - only a partial backup and the final full backup are needed.
Differential backups vs. incremental backups
Both methods allow time-saving backups to be created without requiring excessively large storage capacities. But which option is best for your business? Here are some basic considerations that will get you closer to answering that question.
Consideration 1: How short should your backup cycles be?
Think about what the greatest possible damage could be if you had to fall back on a backup. What data could be lost in the process over the course of a cycle? How much effort would it take to clean up the resulting data loss? What processes might be stalled? Would you perhaps even be forced to inform customers about the data loss?
Consideration 2: How dynamic is your data?
Consider the cycle between two full backups: What do you think the percentage of your data that changes is? After all, if the majority of your data is constantly changing, i.e. very dynamic, an incremental backup will not necessarily require less storage than a differential backup. In this case, the advantages of the latter method outweigh the disadvantages.
Consideration 3: How quickly do you need the backup in an emergency?
Differential backups can be recalled more quickly because only the most recent full backup and the most recent differential partial backup are needed. So if you need it very quickly in an emergency, differential backup is the better option.
The right backup time
Most organizations rely on weekly full backups and daily differential or incremental backups for their backup schedule. To avoid disrupting operations, it's important to think about the best times to create backups.
The weekend is a good time for a full backup, because full backups take the longest. In principle, however, weekdays outside of operating hours can also be considered. However, first test whether the available time window is sufficient to make a full backup in such a case.
Differential or incremental backups are preferably performed at night. In some cases, however, it is also possible to perform the backups so efficiently that there is hardly any disruption to business operations. In this case, the backups can also be performed at other times.
In this way, you ensure that your last backup is always no more than a day old. At the same time, the storage effort is kept within limits and the operational flow is not disturbed.
How many backups are safe enough? The 3-2-1 rule
Is a single backup enough to protect your company data? What if your backup is lost along with the original files? Your data will only be truly safe if you follow the 3-2-1 rule.
3 - Basically, you should always keep three copies of your data: The original (primary system), the backup and yet another backup.
2 - Store the two backups on two different storage media, for example on an external hard drive and additionally in the cloud. This way you reduce the probability of both backup copies failing at the same time.
1 - Store one backup in a different location. The easiest way to do this is in the cloud. This way, even if, for example, your company's geographic location is affected by a natural disaster, that backup will be safe.
In this way, you secure your data in the best possible way and have optimal access to the backups at the same time.
Advantages of differential backup
Differential backups offer a variety of advantages for data protection and thus increase the IT security of your company.
Your backups are faster
Since the entire amount of data does not have to be transferred to the backup medium for each backup, differential backups are significantly faster than full backups.
You need less data storage
With the differential method, you don't back up all files each time, but only the data that has actually changed or been added. This means you can keep the same amount of backups and require significantly less storage capacity.
You back up your data in a resource-saving way
Less data traffic and less data storage - this not only saves costs, but also protects the environment. Differential backups are therefore an important building block on the road to green IT.
You can back up your data at shorter intervals
Differential backups make data backup less time-consuming. If you previously relied on pure full backups, you can now implement more backups at shorter intervals with the same effort and cost. This means you are even better protected in an emergency, because the most recent backup is always more up-to-date.
Disadvantages
Differential backups occupy a middle position between full backup and incremental backup. They are more resource efficient than full backup, but incremental backups can be even more efficient in terms of storage space.
In addition, differential backups are easier to import than incremental backups, with full backups requiring the least effort.
So it depends on the individual case which advantages and disadvantages outweigh the disadvantages and whether differential backups are the optimal solution for your company. In general, the differential and incremental methods are preferable for most companies because they are much more efficient than full backups. The exception to this is small businesses that only have small amounts of data. Here, a full backup may be more advantageous.
How to implement differential backups
How can you take advantage of differential backups for your business? Here we present some best practices.
1. perform a data assessment
The first step toward implementing differential backups is always a data assessment.
To do this, sit down as a team and create a written, complete data inventory. This should take into account all internal processes, data flows and storage locations.
Now perform an assessment. Which of these data pools are absolutely critical to your business processes? And which data would have less of an impact if lost?
For this assessment, also include the expectations of the affected departments as well as external stakeholders. 2.
2. design a backup strategy
Your differential backup should always be embedded in a higher-level backup strategy, which in turn follows a holistic IT strategy.
Topics your backup strategy should address:
What media do we use? Hard disks, tape, NAS or cloud?
How do we ensure geo-redundancy in case our headquarters is affected (fires, floods, earthquakes, etc.).
What are the requirements from IT compliance, both in terms of legal requirements and stakeholder expectations?
Who in the organization is responsible for performing the backup?
3. consider a mix of methods
Full backup, differential backup, incremental backup - it doesn't have to be an either-or decision. After all, it is also possible to combine different variants. In this way, you can achieve short backup cycles with a minimum of time and resources.
For example, a daily full backup could make sense for small, important data stocks in the company, so that this critical data can be restored quickly in the event of an emergency. For the rest of the company's data, on the other hand, a differential or incremental backup might suffice.
Here it helps if you have already performed a data assessment as described above. This allows you to qualitatively differentiate data from one another and adequately back it up.
3. consider BaaS
Despite all the advantages - even differential backups still require a lot of time. Such routine tasks tie up your IT department and slow down the implementation of future projects.
Therefore, consider working with a backup-as-a-service provider (BaaSP). Such specialized managed services providers have a lot of know-how from numerous customer projects; specialized knowledge that is often lacking in-house.
They also guarantee that backups are created on time, which is not always possible in-house. If data is lost, an up-to-date backup is always available.
And last but not least, geo-redundancy is ensured by storing the data in the cloud. In addition, users put a lot of effort into cloud security because their business model depends on it. This benefits your data.
Definition: What is a differential backup?
A differential backup is a backup that includes only the data that has changed or been added since the last full backup. To restore a differential backup, you need the last full backup as well as the latest differential partial backup.
With differential backups, you can implement short backup cycles without requiring huge storage capacities. In addition to the full backup and the differential backup, there are also incremental backups. Often, all three variants are combined in an individual strategy for data backup.
Which methods of data backup exist
In order to understand what role differential backup plays in data protection, the other variants must also be briefly examined: full backup and incremental backup.
Variant 1: The full backup
With the full backup, all data is backed up completely. This makes the full backup the simplest method in terms of handling. This is because all data is backed up at a precisely determinable time and stored in a secure location.
For example, a full backup is created every evening. To import one of the backups later, you simply need the last full backup made.
Variant 1: Full backup
However, the full backup is also the most complex and therefore most expensive method of data backup. It consumes a lot of time to collect and store all data. In addition, for each individual backup you need storage capacity in the size of your entire data volume to be backed up.
Given the relatively high effort and resources required, some companies tend to perform backups too infrequently. In an emergency, often only outdated backups are then available. This is where methods such as differential and incremental backup come into play.
Variant 2: The differential backup
What makes full backups so costly is the fact that each backup stores countless data that rarely or never change. These are then present in multiple copies in each individual backup and occupy storage space.
This is where differential backup comes in. Here, only the data that has really changed or has been newly added is backed up. The basis for this is a full backup, which is made at the beginning. Each subsequent differential backup compares the current data status with this basis and backs up all data that has changed or is new.
For example, a full backup was made on Monday and a differential backup has been made every evening since then. On Friday morning there is a loss of data. To restore Thursday's backup, you need Monday's full backup and Thursday night's differential backup.
Variant 2: Differential backup
This way you can significantly reduce the amount of time and storage capacity needed. But there is a catch: the bigger the differences in the data, the bigger the differential backup will be. Over time, the storage capacity required becomes similar to that of a full backup. The only thing that helps against this is a new full backup as an updated starting point; or you can resort to an incremental backup.
Variant 3: The incremental backup
An incremental backup also saves only new or changed data. But there is a crucial difference to the differential method: the incremental backup does not use the last full backup as a basis, but the last partial backup made. If a data loss occurs, all incremental backups must be restored one after the other in addition to the last full backup.
An example: A full backup was made on Monday and an incremental backup has been made every evening since then. On Friday morning there is a data loss. To restore Thursday's backup, you need Monday's full backup and all incremental backups created up to and including Thursday evening.
This means that the incremental backup backups require the least storage space. The disadvantage is the great effort involved in restoring, because many different backup media have to be handled. This also increases the susceptibility to errors. Here, the differential method has a clear advantage - only a partial backup and the final full backup are needed.
Differential backups vs. incremental backups
Both methods allow time-saving backups to be created without requiring excessively large storage capacities. But which option is best for your business? Here are some basic considerations that will get you closer to answering that question.
Consideration 1: How short should your backup cycles be?
Think about what the greatest possible damage could be if you had to fall back on a backup. What data could be lost in the process over the course of a cycle? How much effort would it take to clean up the resulting data loss? What processes might be stalled? Would you perhaps even be forced to inform customers about the data loss?
Consideration 2: How dynamic is your data?
Consider the cycle between two full backups: What do you think the percentage of your data that changes is? After all, if the majority of your data is constantly changing, i.e. very dynamic, an incremental backup will not necessarily require less storage than a differential backup. In this case, the advantages of the latter method outweigh the disadvantages.
Consideration 3: How quickly do you need the backup in an emergency?
Differential backups can be recalled more quickly because only the most recent full backup and the most recent differential partial backup are needed. So if you need it very quickly in an emergency, differential backup is the better option.
The right backup time
Most organizations rely on weekly full backups and daily differential or incremental backups for their backup schedule. To avoid disrupting operations, it's important to think about the best times to create backups.
The weekend is a good time for a full backup, because full backups take the longest. In principle, however, weekdays outside of operating hours can also be considered. However, first test whether the available time window is sufficient to make a full backup in such a case.
Differential or incremental backups are preferably performed at night. In some cases, however, it is also possible to perform the backups so efficiently that there is hardly any disruption to business operations. In this case, the backups can also be performed at other times.
In this way, you ensure that your last backup is always no more than a day old. At the same time, the storage effort is kept within limits and the operational flow is not disturbed.
How many backups are safe enough? The 3-2-1 rule
Is a single backup enough to protect your company data? What if your backup is lost along with the original files? Your data will only be truly safe if you follow the 3-2-1 rule.
3 - Basically, you should always keep three copies of your data: The original (primary system), the backup and yet another backup.
2 - Store the two backups on two different storage media, for example on an external hard drive and additionally in the cloud. This way you reduce the probability of both backup copies failing at the same time.
1 - Store one backup in a different location. The easiest way to do this is in the cloud. This way, even if, for example, your company's geographic location is affected by a natural disaster, that backup will be safe.
In this way, you secure your data in the best possible way and have optimal access to the backups at the same time.
Advantages of differential backup
Differential backups offer a variety of advantages for data protection and thus increase the IT security of your company.
Your backups are faster
Since the entire amount of data does not have to be transferred to the backup medium for each backup, differential backups are significantly faster than full backups.
You need less data storage
With the differential method, you don't back up all files each time, but only the data that has actually changed or been added. This means you can keep the same amount of backups and require significantly less storage capacity.
You back up your data in a resource-saving way
Less data traffic and less data storage - this not only saves costs, but also protects the environment. Differential backups are therefore an important building block on the road to green IT.
You can back up your data at shorter intervals
Differential backups make data backup less time-consuming. If you previously relied on pure full backups, you can now implement more backups at shorter intervals with the same effort and cost. This means you are even better protected in an emergency, because the most recent backup is always more up-to-date.
Disadvantages
Differential backups occupy a middle position between full backup and incremental backup. They are more resource efficient than full backup, but incremental backups can be even more efficient in terms of storage space.
In addition, differential backups are easier to import than incremental backups, with full backups requiring the least effort.
So it depends on the individual case which advantages and disadvantages outweigh the disadvantages and whether differential backups are the optimal solution for your company. In general, the differential and incremental methods are preferable for most companies because they are much more efficient than full backups. The exception to this is small businesses that only have small amounts of data. Here, a full backup may be more advantageous.
How to implement differential backups
How can you take advantage of differential backups for your business? Here we present some best practices.
1. perform a data assessment
The first step toward implementing differential backups is always a data assessment.
To do this, sit down as a team and create a written, complete data inventory. This should take into account all internal processes, data flows and storage locations.
Now perform an assessment. Which of these data pools are absolutely critical to your business processes? And which data would have less of an impact if lost?
For this assessment, also include the expectations of the affected departments as well as external stakeholders. 2.
2. design a backup strategy
Your differential backup should always be embedded in a higher-level backup strategy, which in turn follows a holistic IT strategy.
Topics your backup strategy should address:
What media do we use? Hard disks, tape, NAS or cloud?
How do we ensure geo-redundancy in case our headquarters is affected (fires, floods, earthquakes, etc.).
What are the requirements from IT compliance, both in terms of legal requirements and stakeholder expectations?
Who in the organization is responsible for performing the backup?
3. consider a mix of methods
Full backup, differential backup, incremental backup - it doesn't have to be an either-or decision. After all, it is also possible to combine different variants. In this way, you can achieve short backup cycles with a minimum of time and resources.
For example, a daily full backup could make sense for small, important data stocks in the company, so that this critical data can be restored quickly in the event of an emergency. For the rest of the company's data, on the other hand, a differential or incremental backup might suffice.
Here it helps if you have already performed a data assessment as described above. This allows you to qualitatively differentiate data from one another and adequately back it up.
3. consider BaaS
Despite all the advantages - even differential backups still require a lot of time. Such routine tasks tie up your IT department and slow down the implementation of future projects.
Therefore, consider working with a backup-as-a-service provider (BaaSP). Such specialized managed services providers have a lot of know-how from numerous customer projects; specialized knowledge that is often lacking in-house.
They also guarantee that backups are created on time, which is not always possible in-house. If data is lost, an up-to-date backup is always available.
And last but not least, geo-redundancy is ensured by storing the data in the cloud. In addition, users put a lot of effort into cloud security because their business model depends on it. This benefits your data.