Backup is part of a disaster recovery plan, not a backup job on its own. A backup service that is bought before the questions “how much data loss can we accept” and “how fast must the system be back” are answered creates disappointment in the middle of a crisis.
How RTO and RPO are defined
The RTO (Recovery Time Objective) is the longest acceptable duration of an interruption. The RPO (Recovery Point Objective) is the acceptable amount of data loss. Both have to be defined together with the business processes, because targets set by a technical team alone are rarely realistic.
- Finance and payroll: RTO in hours, RPO in minutes.
- CRM and customer portal: An RTO of one day is usually tolerable.
- Archiving and reporting: The RTO drops to weeks.
The 3-2-1 rule and modern backup
The 3-2-1 rule still holds: three copies, two different media, one copy off site. Its modern equivalent combines periodic full backups with continuous data protection and replication capable systems. Immutable change logs are the last line of defence against data corruption and ransomware.
Building a four layer backup strategy
- Layer 1 – Image: A full server backup that restores a system quickly after a disaster.
- Layer 2 – File: User data and application files, backed up frequently at file level.
- Layer 3 – Incremental: Stores the changed blocks and reduces both backup time and bandwidth cost.
- Layer 4 – Application consistency: Database logs, mailboxes and configuration files.
Restore testing
The critical step is restoring from the backup. Tests should run at least twice a year with different scenarios: recovering a single file, recovering a complete server and simulating a disaster. The duration of every test has to be recorded and compared against the RTO target.
Write the plan down
The plan must not live only in the head of the person who is responsible. During an outage in the middle of the night, everybody has to know who does what and in which order. The disaster recovery plan needs the communication tree, decision rights and the alternate work site information in writing.
The Serventa 24/7 NOC team prepares backup and disaster recovery plans with your organisation, runs the restore tests and reports the results, so that a disaster does not come with surprises.
