• Copies the changed data since the last full or incremental backup
– This will create incremental dependencies during a restore – Can only restore to last usable incremental backup in sequence
Differential Backup
• Copies all of the changed data since the last full backup
– A restore only requires the last full backup and the latest usable differential backup
We also need to define the type of backup we take.
Some vendors use different terminology but this is the generic, standard terminology.
How often we take a backup would depend on our Recovery Point Objective. If our RPO needed to protect us against data corruption we need a point in time before corruption occurred. Whereas a lot of systems now, that actually do continuous data protection, you will still get some data loss but because of continuous data protection you don’t have to pre-define your RPO because you can go back to multiple points in time. Depending on how you set it up will determine how many copies you hold.