rancher/thin-provisioning-tools

Name: thin-provisioning-tools

Owner: Rancher

Description: null

Created: 2015-04-30 17:55:38.0

Updated: 2016-07-01 17:37:09.0

Pushed: 2015-08-20 00:02:50.0

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Size: 1810

Language: C++

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README

Introduction

A suite of tools for manipulating the metadata of the dm-thin device-mapper target.

Requirements

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.

There are more requirements for testing, detailed below.

Building

./configure
make
sudo make install

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
thinp_restore -i repaired.xml -o /dev/mapper/my_metadata

Development

Autoconf

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

autoreconf
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.

./get-gmock.sh

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

These top level tests are implemented using the cucumber tool. They check the user interface of the tools (eg, command line switches are accepted and effective).

I've provided a Gemfile, so installing this should be easy:

Once you've done this you can run the tests with a simple:

cucumber

Or specific tests with:

cucumber features/thin_restore -n 'print help'

This work is supported by the National Institutes of Health's National Center for Advancing Translational Sciences, Grant Number U24TR002306. This work is solely the responsibility of the creators and does not necessarily represent the official views of the National Institutes of Health.