Table of contents

System Backup Guidance

Related information

System Backup Policy

System Backup Standard

Legacy information

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Backing up information

Backing up is an essential part of protecting Ministry of Justice (MoJ) Information and Communication Technology (IT) resources. This guide document provides an overview of backup concepts, and why backup is important for the MoJ.

It is not normally necessary for you as an individual user to do anything about backing up. Most of the time, it is sufficient for you to know that backups take place, and that it is normally possible to request recovery or restoration of data for a system.

What is backing up?

IT systems fail, or stop working, for many reasons. If you are unlucky, the failure results in the loss of your work. For example, if you are working with a spreadsheet on your desktop computer when the power fails, you lose all the work you have done. Similar problems affect bigger computer systems - servers - too.

Backing up is the process of making a copy of the current information held on the computer system. The copying process usually happens automatically, at regular intervals, often at night. Or it happens when you request it.

The copy of the information is the backup of the data.

A backup lets you recover or restore the data up to the moment the backup was taken, whenever it is needed. Without a proper backup, you have probably lost all your recent work.

A backup helps protect you from the consequences of hardware or software failure, or from accidental or malicious changes to the files and data.

Mirrored or load balanced systems - where the data or services are available from more that one system, and you don’t need to know or care which actual system is being used - are not considered to be forms of backup.

What is data recovery or restoration?

These terms usually mean the thing: data is brought back to be the same as it was at a specific moment in time, or as it was before an event such as accidental deletion.

Why is backing up important?

A backup helps protect you and the MoJ from accidental or deliberate changes to information, for example when data are deleted or IT hardware fails.

Depending on the system used, backups can also provide a history of who made changes to data, and when.

Backups are especially important for record retention requirements. Backups for this purpose are often called archival copies, because each is kept for an extended period of time.

Protecting backups is important. The CESG Information Assurance Maturity Model (IAMM) describes the minimum level of information assurance that all Government departments should provide. For example, access control is a basic assurance requirement. The MoJ backup policy and standard both comply with access control assurance.

More information about how the MoJ backup policy meets the Security Policy Framework mandatory requirement is provided within the IT Security - Technical Controls Policy.

What systems are backed up?

Backup capability is required for all MoJ IT systems, including systems hosted by third party suppliers for the MoJ.

To decide if backup is required for a specific system, ask the question: “how long can the MoJ tolerate the system being unavailable?” If there is any time limit, then backup is probably required.

The Information Asset Owner makes the final decision about whether backup is required for an MoJ system, and what backup schedule should be followed. This is documented within the System Operating Process.

How often does a backup take place?

It depends on many factors, such as the amount of data, the sensitivity of the data, how often it changes, how often you want to restore the data, and how quickly you want it restored.

For example, if some data only changes once a month, backing up the data every day is probably excessive. Similarly, if the data changes every hour, then a daily backup is not enough.

A backup should be taken sufficiently often so that the time required to restore a system to full working state is less than the time for which the MoJ can tolerate the system being unavailable.

Where does a backup go?

Backups are stored in many different places, and on many different media types. Valuable data has many backups, stored in several different places.

Traditionally, backups are stored on one or more of the following backup media:

  • an external drive or USB memory stick

  • a CD or a DVD

  • magnetic tape

More recently, backups are stored on services specifically intended for backups. These services have different performance and availability characteristics to ordinary data processing services. For example, the data might be stored in a different data centre.

Another reason for using backup services is that some systems have so much data that trying to backup to physical media is impractical.

Archival backup media is stored off-line for a defined amount of time. This is for reasons of contract, statutory obligation, or other formal records retention.

Backup media such as tapes should be stored off-site, and only returned on-site when required for data restoration purposes. Storage must be in a secure location that matches the sensitivity of the data. The precise requirements for storing media are outlined in the system Business Continuity Plan (BCP).

What is in a backup?

A backup contains one of:

  • All data, in other words a complete copy of the information on the server. This is called a full backup. It contains all the data needed to restore the system completely, for example after a total system failure.

  • Only data that has been added or changed since the last backup. This is called an incremental backup. But it requires an earlier full backup and previous incremental backups to restore a system completely.

Some backups contain data that is sensitive. Evaluate the data that is to be backed up to decide if it should have extra protection, for example by encrypting the backup.

How long is a backup kept?

Keeping all backups forever on physical media is not practical or desirable. It is usually necessary to delete data and any backups after a defined period of time.

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