SimpleBackups Kompressor - SBK

A format-aware archiver for Minecraft worlds. sbk understands Minecraft's internal file formats and preprocesses them before compression, achieving significantly better ratios than generic archivers like zip or 7z.

Why sbk?

Generic archivers treat world files as opaque blobs. sbk doesn't:

• MCA region files — strips per-chunk zlib/zstd compression, reorders chunks along a Hilbert curve for better spatial locality, then feeds the raw NBT stream into the compressor
• NBT files (.dat, .dat_old) — strips the outer gzip wrapper, stores raw NBT
• JSON files — minifies before compression
• All files are grouped by type and compressed together as solid archives (LZMA2 or Zstd), maximizing cross-file redundancy

The result: roughly 40–55% of original size vs. 70–77% for zip/7z on typical Minecraft worlds.

Benchmarks

Tested on Minecraft 1.21.1 worlds, AMD Ryzen 7 7800X3D, 16 threads:

World size	sbk -l 9	7z -mx=9	zip -9
12.7 MB	20.1%	44.2%	51.4%
129.3 MB	39.1%	68.5%	72.9%
493.3 MB	43.6%	73.0%	76.2%
1.02 GB	44.7%	74.1%	77.0%
1.78 GB	41.9%	72.5%	77.4%

See BENCHMARK.md for full results, including compression and decompression times.

Installation

curl -fsSL https://repo.chaotictrials.de/apt-keyring.gpg \
  | sudo tee /usr/share/keyrings/chaotictrials.gpg > /dev/null
echo "deb [signed-by=/usr/share/keyrings/chaotictrials.gpg] https://repo.chaotictrials.de/ stable main" \
  | sudo tee /etc/apt/sources.list.d/chaotictrials.list
sudo apt update
sudo apt install sbk

Alternatively, download the .deb directly from the Releases page.

Or install via cargo:

cargo install sbk

Or build from source:

cargo build --release
# binary at: target/release/sbk

Usage

Compress a world

sbk compress <world_dir> [OPTIONS]

Option	Default	Description
-o, --output <FILE>	<world_dir>.sbk	Output archive path
-t, --threads <N>	logical CPU count	Worker threads
-l, --level <1–9>	9	Compression level
-a, --algorithm <ALG>	lzma2	Compression algorithm: lzma2 or zstd
--max-age <MS>	—	Skip files not modified in the last N ms
--since <TIMESTAMP>	—	Skip files with mtime below Unix timestamp (ms)
--exclude <PATTERN>…	—	Exclude files matching glob patterns (repeatable)
--include <PATTERN>…	—	Include ONLY files matching glob patterns (repeatable)
--include-session-lock	off	Include session.lock (excluded by default)
-q, --quiet	off	Suppress progress bars, summary, and non-fatal warnings

--exclude and --include are mutually exclusive.

Multi-pattern usage

Both flags accept one or more patterns in a single invocation. Three safe forms:

# 1. world_dir before the flag (most common)
sbk compress world_dir --exclude "*.zip" "*.dat_old"

# 2. Repeat the flag once per pattern
sbk compress world_dir --exclude "*.zip" --exclude "*.dat_old"

# 3. Use -- to separate world_dir from patterns when world_dir comes last
sbk compress --exclude "*.zip" "*.dat_old" -- world_dir

Decompress

sbk decompress <file.sbk> [-o <dir>] [-t <threads>]

Extract specific files

sbk extract <file.sbk> <pattern>... [-o <dir>]

Patterns are glob expressions (e.g. region/*.mca, level.dat).

Show archive info

sbk info <file.sbk> [--list]

--list prints the full file manifest as a tree, with file type and size for each entry.

Convert between SBK and standard archive formats

sbk convert works in both directions:

SBK → zip / tar.gz / tar.xz

sbk convert <file.sbk> --to <format> [-o <output>] [-t <threads>] [-l <level>]

sbk convert world.sbk --to zip
sbk convert world.sbk --to tar.gz -o backup.tar.gz
sbk convert world.sbk --to tar.xz -l 9

zip / tar.gz / tar.xz → SBK

sbk convert <archive> [-o <output.sbk>] [-t <threads>] [-l <level>] [-a <algo>]

sbk convert world.zip
sbk convert world.tar.gz -o world.sbk
sbk convert world.tar.xz --algorithm zstd

Option	Default	Description
--to <format>	auto (sbk when input is not .sbk)	Target format: zip, tar.gz, tar.xz, sbk
-o, --output <FILE>	<archive_stem>.<ext>	Output file path
-t, --threads <N>	logical CPU count	Worker threads
-l, --level <1–9>	6	Compression level for the output format
-a, --algorithm <ALGO>	lzma2	Algorithm for output SBK: lzma2 or zstd

When converting SBK → other formats, files are reconstructed in memory and streamed into the output archive with no temporary directory. When converting other formats → SBK, the input archive is extracted to a temporary directory and then compressed with the same pipeline as sbk compress.

Verify integrity

sbk verify <file.sbk>

Checks xxHash32 checksums of all frames.

SBK format

An .sbk file consists of:

1. Header (79 bytes) — magic SBK!V1\r\n, file counts, offsets, xxHash32 header checksum
2. Data blocks — four solid streams (one per file group: MCA, NBT, JSON, RAW), compressed with LZMA2 or Zstd as selected at compress time
3. Frame directory — per-frame offsets, sizes, and xxHash32 checksums
4. Index block — sorted file manifest, compressed with the same algorithm as the data blocks

All integers are little-endian. Frame size is 16 MiB uncompressed. See SPEC.md for the full format specification.