Introduction to LVM2
        
        
          The LVM2 package is a set of tools
          that manage logical partitions. It allows spanning of file systems
          across multiple physical disks and disk partitions and provides for
          dynamic growing or shrinking of logical partitions, mirroring and
          low storage footprint snapshots.
        
        
          This package is known to build and work properly using an LFS 12.4
          platform.
        
        
          Package Information
        
        
          
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                Download (HTTP): https://sourceware.org/ftp/lvm2/LVM2.2.03.34.tgz
               
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                Download MD5 sum: 947741079e22a35d76aefa99861b406a
               
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                Download size: 2.8 MB
               
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                Estimated disk space required: 41 MB (add 20 MB for tests;
                transient files can grow up to around 300 MB in the /tmp
                directory during tests)
               
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                Estimated build time: 0.2 SBU (add 9 to 48 SBU for tests,
                depending on disk speed and whether ram block device is
                enabled in the kernel)
               
 
        
          LVM2 Dependencies
        
        
          Required
        
        
          libaio-0.3.113
        
        
          Optional
        
        
          libnvme-1.15, mdadm-4.4, Valgrind-3.25.1, Which-2.23, xfsprogs-6.15.0 (latter
          four may be used, but are not required, for tests), 
          reiserfsprogs, thin-provisioning-tools,
          and vdo
        
       
      
        
          Kernel Configuration
        
        
          Enable the following options in the kernel configuration and
          recompile the kernel:
        
        
          ![[Note]](../images/note.png) 
          
            Note
          
          
            There are several other Device Mapper options in the kernel
            beyond those listed below. In order to get reasonable results if
            running the regression tests, all must be enabled either
            internally or as a module. The tests will all time out if Magic
            SysRq key is not enabled.
          
         
        Device Drivers --->
  [*] Block devices --->                                               [BLK_DEV]
    <*/M> RAM block device support                                 [BLK_DEV_RAM]
  [*] Multiple devices driver support (RAID and LVM) --->                   [MD]
    <*/M> Device mapper support                                     [BLK_DEV_DM]
    <*/M>   Crypt target support                                      [DM_CRYPT]
    <*/M>   Snapshot target                                        [DM_SNAPSHOT]
    <*/M>   Thin provisioning target                      [DM_THIN_PROVISIONING]
    <*/M>   Cache target (EXPERIMENTAL)                               [DM_CACHE]
    <*/M>   Mirror target                                            [DM_MIRROR]
    <*/M>   Zero target                                                [DM_ZERO]
    <*/M>   I/O delaying target                                       [DM_DELAY]
Kernel hacking --->
  Generic Kernel Debugging Instruments --->
    [*] Magic SysRq key                                            [MAGIC_SYSRQ]
       
      
        
          Installation of LVM2
        
        
          Install LVM2 by running the
          following commands:
        
        PATH+=:/usr/sbin                \
./configure --prefix=/usr       \
            --enable-cmdlib     \
            --enable-pkgconfig  \
            --enable-udev_sync  &&
make
        
          The tests use udev for logical
          volume synchronization, so the LVM udev rules and some utilities
          need to be installed before running the tests. If you are
          installing LVM2 for the first
          time, and do not want to install the full package before running
          the tests, the minimal set of utilities can be installed by running
          the following instructions as the root user:
        
        make -C tools install_tools_dynamic &&
make -C udev  install               &&
make -C libdm install
        
          To test the results, issue, as the root user:
        
        LC_ALL=en_US.UTF-8 make check_local
        
          Some tests may hang. In this case they can be skipped by adding
          S=<testname> to
          the make command.
          Other targets are available and can be listed with make -C test help. The test
          timings are very dependent on the speed of the disk(s), and on the
          number of enabled kernel options.
        
        
          The tests do not implement the “expected fail” possibility, and a small
          number of test failures is expected by upstream. More failures may
          happen because some kernel options are missing. For example, the
          lack of the dm-delay device
          mapper target explains some failures. Some tests may fail if there
          is insufficient free space available in the partition with the /tmp
          directory. At least one test fails if 16 TB is not available. Some
          tests are flagged “warned” if thin-provisioning-tools
          are not installed. A workaround is to add the following flags to
          configure:
        
             --with-thin-check=    \
     --with-thin-dump=     \
     --with-thin-repair=   \
     --with-thin-restore=  \
     --with-cache-check=   \
     --with-cache-dump=    \
     --with-cache-repair=  \
     --with-cache-restore= \
        
          Some tests may hang. They can be removed if necessary, for example:
          rm
          test/shell/lvconvert-raid-reshape.sh. The tests
          generate a lot of kernel messages, which may clutter your terminal.
          You can disable them by issuing dmesg
          -D before running the tests (do not forget to issue
          dmesg -E when tests
          are done).
        
        
          ![[Note]](../images/note.png) 
          
            Note
          
          
            The checks create device nodes in the /tmp directory. The tests
            will fail if /tmp is mounted with the nodev option.
          
         
        
          Now, as the root user:
        
        make install
make install_systemd_units
       
      
        
          Command Explanations
        
        
          PATH+=:/usr/sbin: The
          path must contain /usr/sbin for
          proper system tool detection by the configure script. This
          instruction ensures that PATH is properly set even if you build as
          an unprivileged user.
        
        
          --enable-cmdlib: This
          switch enables building of the shared command library. It is
          required when building the event daemon.
        
        
          --enable-pkgconfig: This
          switch enables installation of pkg-config support files.
        
        
          --enable-udev_sync: This
          switch enables synchronisation with Udev processing.
        
        
          --enable-dmeventd: This switch enables
          building of the Device Mapper
          event daemon.
        
        
          make
          install_systemd_units: This is needed to install a
          unit that activates logical volumes at boot. It is not installed by
          default.