Backup and recovery is software that copies a company's servers, virtual machines and databases on a schedule, and brings them back after a failure, a mistake or an attack. Bringing data back from a backup is called a restore.
A backup plan rests on two numbers. The recovery point objective (RPO) is how much recent data the company can afford to lose. If backups run every four hours, up to four hours of work can be lost. The recovery time objective (RTO) is how long the company can afford to wait while its systems are restored. A bank's payment system may need an RTO of minutes. An old archive may be allowed several days.
Take, for example, a car-parts factory in Hosur that runs three shifts a day. Its ERP system, the software that records every order, every stock movement and every invoice, runs on one database. Its production software runs on 40 virtual machines. The IT team sets a policy. The database is copied every hour. The virtual machines are copied every night at 1 a.m. The copies are kept on disk for 30 days. After that, they are moved to tape and kept for several years, as tax and GST rules require.
The first backup is a full copy. After that, the software copies only the blocks of data that have changed since the last backup. This is called an incremental backup. The software also stores repeated data only once. For example, the same operating system files sit on all 40 virtual machines, but the backup keeps one copy of them. This is called deduplication. So each night's backup takes minutes instead of hours, and it uses a small part of the space.
At 10 a.m. one Tuesday, an employee in the stores team deletes a month of stock records by mistake. The IT team restores the database to the copy made at 9 a.m. Only one hour of entries must be typed in again.
Backup software now does security work as well, because ransomware attackers try to delete the backups before they lock the live data. So the software keeps an immutable backup, which no one can change or delete. It keeps an air-gapped backup, which the company's network cannot reach. It watches the backups for signs of an attack, such as thousands of files suddenly changing in one night. It also checks every login to the backups, even an administrator's, which follows the idea of zero trust. After an attack, ransomware recovery restores the systems in a sealed-off area first.
Backup software can run on the company's own hardware, or be bought entirely as a cloud service, with no backup hardware at the customer at all. Laptops and rented browser apps need their own tool, SaaS and endpoint backup.