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pepe ab3e59860c :) 2 weeks ago
autoconf more build stuff 12 years ago
base [thin] Adopt stateful random number generators 3 years ago
bin :) 2 weeks ago
block-cache [all] Eliminate duplicated sector_t typedefs 3 years ago
caching [all] Eliminate duplicated sector_t typedefs 3 years ago
contrib autoconf: allow a user to override ar 3 years ago
doc [thin_journal_check] Checks journal of block manager activity. 5 years ago
era [space-maps/core] rewrite the core space map to use less memory. 3 years ago
features [functional-tests] era_check tests 6 years ago
ft-lib [ft-lib/bcache] rename raise() -> raise_() 4 years ago
functional-tests [thin_check] rename --fix-metadata-leaks to --auto-repair 3 years ago
lib gmock stub 10 years ago
man8 [thin_check] rename --fix-metadata-leaks to --auto-repair 3 years ago
persistent-data [metadata_checker] Support in-place metadata space map modification 3 years ago
tests [thin_shrink] add a trivial snapshot test. 3 years ago
thin-provisioning [thin_check] rename --fix-metadata-leaks to --auto-repair 3 years ago
ui [thin_show_metadata] ncurses render 7 years ago
unit-tests [unit-tests] Add test cases for space maps 3 years ago
xml_metadata add some example metadata dumps 12 years ago
.gitignore [rust tools] Get the tools version from autoconf 3 years ago
CHANGES [build] Update CHANGES file 3 years ago
COPYING Add copyright 12 years ago :) 2 weeks ago [thin_metadata_pack/unpack] Replace C++ implementation with a Rust one. 3 years ago Add a TODO file 10 years ago
VERSION bump version to 0.9.0 3 years ago [build] Fix the default value for the AR variable (#145) 3 years ago update get-gmock script. 7 years ago [base] introduce a command type that gets registered with the app 8 years ago
mk_release make mk_release executable 11 years ago
rustfmt.toml [thin_metadata_pack/unpack] Replace C++ implementation with a Rust one. 3 years ago 12 years ago


A suite of tools for manipulating the metadata of the dm-thin, dm-cache and dm-era device-mapper targets.


A C++ compiler that supports the c++11 standard (eg, g++). The Boost C++ library. The expat xml parser library (version 1). The libaio library (note this is not the same as the aio library that you get by linking -lrt) make, autoconf etc.

A couple of non-essential tools are written in rust, and will require cargo and rustcc to be installed:


There are more requirements for testing, detailed below.


sudo make install

Building Rust tools

sudo make install-rust-tools

Quick examples

These tools introduce an xml format for the metadata. This is useful for making backups, or allowing scripting languages to generate or manipulate metadata. A Ruby library for this available; thinp_xml.

To convert the binary metadata format that the kernel uses to this xml format use thin_dump.

thin_dump --format xml /dev/mapper/my_thinp_metadata

To convert xml back to the binary form use thin_restore.

thin_restore -i my_xml -o /dev/mapper/my_thinp_metadata

You should periodically check the health of your metadata, much as you fsck a filesystem. Your volume manager (eg, LVM2) should be doing this for you behind the scenes.

thin_check /dev/mapper/my_thinp_metadata

Checking all the mappings can take some time, you can omit this part of the check if you wish.

thin_check --skip-mappings /dev/mapper/my_thinp_metadata

If your metadata has become corrupt for some reason (device failure, user error, kernel bug), thin_check will tell you what the effects of the corruption are (eg, which thin devices are effected, which mappings).

There are two ways to repair metadata. The simplest is via the thin_repair tool.

thin_repair -i /dev/mapper/broken_metadata_dev -o /dev/mapper/new_metadata_dev

This is a non-destructive operation that writes corrected metadata to a new metadata device.

Alternatively you can go via the xml format (perhaps you want to inspect the repaired metadata before restoring).

thin_dump --repair /dev/mapper/my_metadata > repaired.xml
thin_restore -i repaired.xml -o /dev/mapper/my_metadata



If you've got the source from github you'll need to create the configure script with autoconf. I do this by running:


Enable tests

You will need to enable tests when you configure.

./configure --enable-testing

Unit tests

Unit tests are implemented using the google mock framework. This is a source library that you will have to download. A script is provided to do this for you.


All tests can be run via:

make unit-test

Alternatively you may want to run a subset of the tests:

make unit-tests/unit_tests
unit-tests/unit_tests --gtest_filter=BtreeTests.*

Functional tests

A bunch of high level tests are implemented in the functional-tests directory. These tests are written in Scheme. To run them you'll need to install chezscheme ( There is no longer a dependency on the ThunderChez library.

Make sure the tools that you wish to test are in your PATH.


cd funtional-tests
./run-tests run

Other command are help and list.

The test framework places temporary files under ./test-output/. By default the tests tidy up after themselves, just leaving a log file for each test. You can turn this off by using the --disable-unlink flag if you want all the artifacts left.

Dump Metadata

To dump the metadata of a live thin pool, you must first create a snapshot of the metadata:

$ dmsetup message vg001-mythinpool-tpool 0 reserve_metadata_snap

Extract the metadata:

$ sudo bin/thin_dump -m /dev/mapper/vg001-mythinpool_tmeta
<superblock uuid="" time="1" transaction="2" data_block_size="128"nr_data_blocks="0">
    <device dev_id="1" mapped_blocks="1" transaction="0" creation_time="0" snap_time="1">
        <single_mapping origin_block="0" data_block="0" time="0"/>
    <device dev_id="2" mapped_blocks="1" transaction="1" creation_time="1" snap_time="1">
        <single_mapping origin_block="0" data_block="0" time="0"/>

Finally, release the root:

$ dmsetup message vg001-mythinpool-tpool 0 release_metadata_snap