Backup Types & Compression

Understanding how Just Enough Backups structures data helps you balance backup speed, disk space, and safety.

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The Three Backup Types

Type	Reference Point	Contents	Speed	Disk Usage
Full	None	Entire world snapshot.	Slower	Largest
Partial	Most recent compatible backup of any type	Files changed since that backup.	Usually fastest	Usually smallest
Differential	Most recent Full backup	Files changed since that Full backup.	Fast	Grows until the next Full

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Visualizing Backup Chains

Chain Type	Base Reference	How it Works
📦 Full Backup	None (Root)	Complete standalone world snapshot. Foundation for subsequent backups.
⚡ Partial Chain	Preceding backup	Each archive records changes since the previous backup: Full #1 → Partial #1 → Partial #2
🛡️ Differential Chain	Base Full only	Each archive records all changes since the base Full: Full #1 → Differential #1 / Differential #2

Partial chain

Full #1Complete snapshot→Partial #1Changes since Full #1→Partial #2Changes since Partial #1

Differential

Full #1Complete snapshot→

Differential #1Changes since Full #1Differential #2Also since Full #1

Partial backups use the most recent backup of any type as their reference. Differential backups each compare against the most recent Full snapshot.

Which should I use?

• Full: Take these periodically (e.g. once a week or once a month) as solid recovery anchor points.
• Partial: Ideal for frequent automatic runs (e.g. hourly). They take seconds to create and use minimal disk space.
• Differential: Great for daily runs. If an intermediate daily backup is ever deleted, subsequent differential backups still restore directly against the Full backup.

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Automatic Dependency Protection

In basic backup tools, deleting an old Full backup to save space corrupts any incremental backups made after it.

IMPORTANT

JEB protects required bases: JEB tracks the dependency tree of every archive. If a retention rule marks an old Full backup for removal, JEB will keep it protected as long as at least one active Partial or Differential backup depends on it.

The parent backup is only deleted once all dependent child backups have expired or been removed.

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Compression Engines: Deflate vs Zstandard

Archives use the .zip container with one of two compression methods:

Feature	DEFLATED	ZSTANDARD
ZIP Method	Method 8 (Standard)	Method 93
Speed	Standard	Extremely Fast
Compression Ratio	Often good	Depends on the world data; benchmark your own world
Config Level Range	1 – 9 (Default: 6)	1 – 22 (Default: 3)
Compatibility	Opens in any OS tool	Built into JEB, requires 7-Zip v22+ externally

Standard Deflate

{
  "compressionMethod": "DEFLATED",
  "deflateCompressionLevel": 6
}

Zstandard (Recommended for Large Servers)

{
  "compressionMethod": "ZSTANDARD",
  "zstdCompressionLevel": 3
}

Memory Protection

For Zstandard compression, JEB uses temporary scratch files for large entries to limit memory use. Ensure the temporary directory has enough free space; this reduces memory pressure but cannot guarantee that an out-of-memory error is impossible.

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Free Space Pre-Flight Check

Before starting an archive, JEB checks available disk space on the backup drive:

Required Free Space ≈ (estimated archive size * 2) + minimumFreeSpaceReserveMb

JEB estimates archive size from changed files and the last full backup's compression ratio. If temporary and destination directories are on different drives, it checks both. This preflight estimate cannot guarantee that a drive will not fill during a backup.