Estimating storage for your backups

The storage required for backups depends mainly on how much data you have, how often it changes, and your retention policy.

Snaper minimizes storage usage through deduplication, compression, and incremental snapshots, meaning only new or modified data is stored between backups.

File Backups

For file-level backups, two mechanisms significantly reduce storage usage:

  • File deduplication – identical files are stored only once.
  • Compression – files are compressed before being stored. Text-based files (configs, code, etc.) can sometimes shrink by up to 95%.

As a result, storage growth mostly depends on how much data changes between backups, not the total size of your filesystem.

Database Backups

For databases, Snaper performs a dump followed by compression.

On average, database dumps compress by about 80%.

Example:

  • Database size: 100 MB
  • Compressed backup: ~20 MB

With daily backups for 30 days, the required storage would normally be approximately:

30 × 20 MB ≈ 600 MB

However, we apply by default a degressive retention policy that keeps fewer backups as they get older, which further reduces long-term storage needs (see below).

Retention Policies

Snaper uses retention policies to control how long backups are kept.

By default, it uses a degressive retention policy, which keeps recent backups more frequently and older ones less frequently:

  • Daily backups for 7 days
  • 3 backups per week for the next 4 weeks
  • 1 backup per week for 3 months
  • 1 backup per month afterward

This approach significantly reduces long-term storage requirements while keeping enough restore points.

Example: E-commerce Website

For an infrastructure with:

  • 200 GB of files
  • 60 GB database

Using Snaper’s compression, deduplication, and degressive retention policy, a full year of backups would typically require around 600 GB of storage.