⚠️ Important note
Master branch is compatible only with latest work for upstream kernel integration. See patchsets for linux kernel in directory patches or in Linux kernel fork branches.
ℹ️ standalone blksnap module
The standalone blksnap kernel module, which is included in the Veeam Agent for Linux product, is available in branches, whose names correspond to the product version. For example, the VAL-6.0 branch is used to build packages for Veeam Agent for Linux 6.0. It is recommended to use the latest branch, as it is likely to support the latest version of the Linux kernel and implement fixes and improvements. You can use it according to its license.
ℹ️ to Veeam Agent for Linux users:
If you have any questions when using Veeam Software products, please contact the official support service. Use the product components received from official Veeam Software representatives in accordance with the user guide.

BLKSNAP - Block Devices Snapshots

• Extended description and features
• Repository structure
• Licensing
• Upstream kernel integration
• Tools
• Library
• Tests
  • Details:
    • Boundary
    • Corrupt
    • Diff storage
• Compatibility notes
• Contributing

Repository structure

• doc/ - Documentation
• include/ - Libraries public headers
• lib/ - Libraries sources
• patches/ - Patches for the upstream linux kernel
• pkg/ - Scripts for building deb and rpm packages
• tests/ - Test scripts and tests source code
• tools/ - Source files of tools for working with blksnap

Licensing

Kernel module is GPL-2 only, tools and tests are GPL-2+, library and include are LGPL-3+.

Copyright (C) 2022 Veeam Software Group GmbH

This project use SPDX License Identifier in source files header.

Kernel integration

For details about the work in progress for integration in upstream kernel see the specific README

Tools

The blksnap tools allows you to manage the module from the command line. The program allows for execution of individual ioctls of the blksnap module. The interface of the program may seem inconvenient to the user, since it is assumed that it will be called by other applications.

How to build

See how to build library, tools and tests

Library

The dynamic C library is not needed to work with blksnap. File ./include/blksnap/blksnap.h contains everything you need to work with blksnap. But to demonstrate how to call the ioctl, a static c++ library was created. The library can also help you quickly create a working prototype. In the project, the library is used for tests.

How to build

See how to build library, tools and tests

Tests

The test scripts are written in bash and use the blksnap tool to control the blksnap module. The test scripts allow to check the main functions of the module. To implement complex test algorithms, С++ tests are implemented. C++ tests use the static library libblksnap.a and it must be compiled to build С++ tests.

How to build

See how to build library, tools and tests

How to run all usage tests

# change working directory to the tests one, for example for debian package is /opt/blksnap/tests
cd /opt/blksnap/tests
# execute all tests script
sudo ./all.sh
# or for logging the output to a file
sudo ./all.sh 2>&1 | tee -a /tmp/blksnap_test_$(date -u '+%Y-%m-%d_%H-%M-%S').log

How to build library, tools and tests

Installing the necessary deb packages.

sudo apt install g++ cmake uuid-dev libboost-program-options-dev libboost-filesystem-dev libssl-dev

Or installing the necessary rpm packages.

sudo yum install g++ cmake libuuid-devel boost-static libstdc++-static openssl-static

Build.

cmake .
make

Install (but it is recommended to use packages instead, for example the debian ones)

sudo make install

Uninstall (if needed)

sudo make uninstall

How to create dev, tools and tests deb packages

sudo apt install g++ cmake uuid-dev libboost-program-options-dev libboost-filesystem-dev libssl-dev debhelper
cd ./pkg/deb
./build-blksnap.sh ${VERSION}

Compatibility notes

• blksnap kernel module for upstream can support any arch (other archs beyond X86 archs needs more testing)
• all supported debian and ubuntu supported versions are supported but with some notes:
  • debian 8 and ubuntu 14.04 needs to install cmake 3 from backports to build