What is a backup repository?
A backup repository is the storage location where backup software writes and keeps restore points. It can be a server with local disks, a network share, a deduplication appliance or object storage, and it is the component whose loss means the loss of the backups themselves.
What types of backup repository are there?
Repositories differ in how the backup software reaches them and in what the storage does with the data.
| Type | How it is reached | Typical use |
|---|---|---|
| Direct-attached or local disk | Block device on the repository server | Small estates, fast local restores |
| NAS share | SMB or NFS | Simple shared target, limited protection |
| Deduplication appliance | Proprietary protocol or share | Long retention with high data reduction |
| Hardened Linux repository | Backup software data mover | Immutability on a single server |
| Object storage | S3 API | Scalable target with Object Lock immutability |
How is a backup repository different from a backup target?
The terms overlap. Backup target usually means the storage system that receives backup data. Repository is the name backup software gives to a target once it has been configured with a path, credentials, limits and retention behaviour. One storage system can host several repositories.
What decides the size of a backup repository?
Capacity depends on the amount of protected data, the daily change rate, the retention schedule, the data reduction achieved and growth over the planning period. Immutability adds to it, because locked restore points cannot be removed early. Backup repository sizing sets out the calculation.
How is a backup repository protected?
A repository is a primary target in ransomware incidents, because deleting backups removes the alternative to paying. Protection rests on three things: separate credentials that do not depend on the production directory, a network position that exposes only what the backup software needs, and immutability enforced by the storage so that restore points cannot be changed or deleted before their retention ends.
Frequently asked questions
Can one backup server use several repositories?
Yes. Most backup software can write to many repositories and group them, for example into a performance tier and a capacity tier.
Should a backup repository be joined to the production domain?
Generally not. A repository that trusts the production directory can be reached with stolen domain credentials.
Is cloud object storage a backup repository?
It can be. Backup software that supports the S3 API can use a cloud or on-premises object store as a repository.