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Conserve: a robust backup program

Linux build status Windows build status Join the chat at Maturity: Alpha

Conserve's guiding principles:

  • Safe: Conserve is written in Rust, a fast systems programming language with compile-time guarantees about types, memory safety, and concurrency. Conserve uses a conservative log-structured format.

  • Robust: If one file is corrupted in storage or due to a bug in Conserve, or if the backup is interrupted, you can still restore what was written. (Conserve doesn't need a large transaction to complete for data to be accessible.)

  • Careful: Backup data files are never touched or altered after they're written, unless you choose to purge them.

  • When you need help now: Restoring a subset of a large backup is fast.

  • Always making progress: Even if the backup process or its network connection is repeatedly killed, Conserve can quickly pick up where it left off and make forward progress.

  • Ready for today: The storage format is fast and reliable on on high-latency, limited-capability, unlimited-capacity, eventually-consistent cloud object storage. Conserve is tested on Windows, Linux (x86 and ARM), and OS X.

Quick start guide

Conserve storage is within an archive directory created by conserve init:

conserve init /backup/home.cons

conserve backup copies a source directory into a new version within the archive. Conserve copies files, directories, and (on Unix) symlinks. If the conserve backup command completes successfully (copying the whole source tree), the backup is considered complete.

conserve backup /backup/home.cons ~

conserve versions lists the versions in an archive, whether or not the backup is complete, the time at which the backup started, and the time taken to complete it. Each version is identified by a name starting with b.

$ conserve versions /backup/home.cons
b0000                      complete   2016-11-19T07:30:09+11:00     71s
b0001                      incomplete 2016-11-20T06:26:46+11:00
b0002                      incomplete 2016-11-20T06:30:45+11:00
b0003                      complete   2016-11-20T06:42:13+11:00    286s
b0004                      complete   2016-12-01T07:08:48+11:00     84s
b0005                      complete   2016-12-18T02:43:59+11:00      4s

conserve ls shows all the files in a particular version. Like all commands that read a band from an archive, it operates on the most recent by default, and you can specify a different version using -b. (You can also omit leading zeros from the backup version.)

$ conserve ls -b b0 /backup/home.cons | less

conserve restore copies a version back out of an archive:

$ conserve restore /backup/home.cons /tmp/trial-restore

conserve validate checks the integrity of an archive:

$ conserve validate /backup/home.cons


The --exclude GLOB option can be given to commands that operate on files, including backup, restore, ls and list-source.

A / at the start of the exclusion pattern anchors it to the top of the backup tree (not the root of the filesystem.) ** recursively matches any number of directories.

At the moment exclusion patterns must always start from the root, so you need **/*.swp to exclude .swp files anywhere in the tree.

The syntax is comes from the Rust globset crate.


To build Conserve you need Rust and a C compiler that can be used by Rust.

To install the most recent release from, run

cargo install conserve

To install from a git checkout, run

cargo install -f --path .

Binaries for some platforms are available from

On nightly Rust only, you can enable a potential speed-up to the blake2 hashes with

rustup run nightly cargo build --release --features blake2-rfc/simd_asm

More documentation


Conserve is reasonable to use today, with regard to format and performance, but still pre-1.0.

Be aware that Conserve is developed as a (very) part-time non-commercial project and there's no guarantee of support.

The format may well change again before 1.0. To use any archive written by Conserve 0.x.y, you need to use Conserve 0.x. (Previous versions will always be available from git or

Some other limitations:

Prior to 1.0, data formats may change on each minor version number change (0.x): you should restore using the same version that you used to make the backup.

For a longer list see the issue tracker and milestones.

Windows Defender and Windows Search Indexing can slow the system down severely when Conserve is making a backup. I recommend you exclude the backup directory from both systems.

Licence and non-warranty

Copyright 2012-2019 Martin Pool,

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

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