SME Data Backup

Differential backup: the smart alternative

Backing up company-relevant and customer-specific data has long since become a business success criterion. In order to decide on a form of backup that is suitable for your company, you must first be clear about which data needs to be backed up, how frequently, and what downtime could be afforded in the worst case. If the backup is performed differentially, even frequent changes to data can be reliably backed up within short periods of time.

What is differential backup?

Differential backup is a method where changes are saved in relation to the last complete backup. This means that first a complete backup is saved on a disk. If changes are made shortly afterwards, these changes are saved separately on another data carrier. If further adjustments are made, all the data that has changed since the last complete backup is saved in this way.

A differential backup enables relevant data to be stored more quickly and can reliably back up a large number of data changes. However, in order to implement such a differential backup, a high level of storage capacity is required, since with each new backup created, all data already saved since the last full backup is also saved again. A certain amount of data redundancy cannot be avoided.

Differentiation from other backup types

The simplest form of backup is the full backup or the complete backup. Here, all existing data is backed up at the end of each specified period, for example on the Friday of a week. The disadvantage of this is the high storage capacity required and the correspondingly large amount of time needed. In the event of a disaster, only the last backup would be needed. However, only this backup would be available.

A classic form of complete backup would also be the generation or grandfather-father-son principle. Here, backups of the entire existing data are made at different times. If a downstream backup is lost ("son"), the lost data can be restored from the information in the upstream backup ("father"). Applied, this could mean that a full backup is created each day ("son"), which is overwritten with the current data on the following days of the coming week. On Friday, additional backups of the entire week's events would be made, which would remain unwritten ("Father"). On the last day of the month, an additional complete backup of all data created in the month in question would be made, which would also be stored separately ("grandfather"). After one month, the last weekly backup would be overwritten for the first time, and after one year, the monthly backup. Data stored one year earlier could thus be restored in case of loss. Unlike differential backup, generational backup intentionally creates long-term redundancy. More storage capacity is required, which means more time is needed.

Another data backup concept is incremental backup. Here, changes and adjustments are saved separately in shorter periods of time and until the next complete backup. In terms of a week, this would mean that a full backup would be created at the weekend. Changes that occur on the following Monday would be backed up using a hard disk. Changes occurring on Tuesday would again be stored on another disk, and so on.

Differential backup would back up changes similarly, but without creating a separate backup for each day. On Monday all adjustments of the day would be saved, on Tuesday all changes that occurred on that day including the changes already saved on Monday. On Wednesday, Monday and Tuesday would be recorded again in addition to Wednesday events, and so on until the end of the week. Whether a backup is incremental or differential depends on the importance and security classification of the data being backed up. While the incremental method would require both the last full backup and any change backups saved thereafter, if one has performed a differential backup, one would only need the last full backup and the last backup to allow recovery of the data. Moreover, if one is looking for a specific file, it will be faster to find it on only 2 backups.

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Consideration in the backup strategy of a company

A differential backup is especially useful for companies that make frequent adjustments to data and want to keep it safe at all times. The security classification of the data to be backed up should therefore be clearly defined. Such data could be order data, for example. It must also be clear how much space is available for storing the storage media and at what intervals the differential backup is to take place (hourly, daily, weekly). It must also be clear when complete backups are to be performed. Depending on the volume of data, a decision can be made as to whether differential backup is the best solution.

Restore differential backup: How does it work?

If a differential backup is to be restored, the medium described with the differential backup must be compared with the last complete backup.

Differential backup on tapes: Does it make sense in the long run?

Larger data volumes of about 3-4 terabytes can be stored on magnetic tapes. If their integrity is checked regularly, they are very safe and take up little space. They are less susceptible to mechanical stress than hard disks, for example, but even tapes cannot withstand electromagnetic stress without damage. After 5-6 years, the tapes must be re-stored to prevent adverse effects due to deteriorating magnetization.

Differential backup to external hard disk

A differential backup should be stored on an external hard disk, for example, to prevent losses due to technical failures or access by unauthorized third parties. For smaller companies, it is also advisable to store backup media such as tapes and hard disks in safe deposit boxes or similar. Larger companies can also use specially secured rooms (cells).

Differential backup: dealing with the archive bit

Differential backup requires marking the data to be backed up with an archive bit. Such marking is done with the help of a bit. By default, the data to be backed up is marked with a tick (bit) that initiates its backup. After the changed data has been backed up, the marking must be removed accordingly so that only edited data is saved when the next backup is performed.

Langmeier Backup: the right solution for every company

Are you looking for a reliable and uncomplicated form of data backup and appropriate software for your company? Langmeier offers various backup solutions for companies. The tools offered by Langmeier are equally suitable for RAID data backup, the creation of an EDP backup copy or a Microsoft backup. The Business Package is a suitable data backup option for large companies, but also interesting and usable as a backup solution for small businesses. Whichever backup option you choose, Langmeier has a solution tailored to your company that will ensure long-term success.

Langmeier Backup

Backup for Windows

  Buy Now   Try it for free
Backup software for Windows

About the Author Alexander Vogt
1st and 2nd level support

Our solutions make it easy to set up automations to minimize your workload and take efficiency to a new level. Every day, we strive to deliver peak performance and support you. As the leader for 1st and 2nd level support, I am your best point of contact for questions related to the implementation of our applications.



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