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LVM.CONF(5)                   File Formats Manual                  LVM.CONF(5)



NAME
       lvm.conf - Configuration file for LVM2

SYNOPSIS
       /etc/lvm/lvm.conf

DESCRIPTION
       lvm.conf is loaded during the initialisation phase of lvm (8).  This
       file can in turn lead to other files being loaded - settings read in
       later override earlier settings.  File timestamps are checked between
       commands and if any have changed, all the files are reloaded.

       Use lvm dumpconfig to check what settings are in use.

SYNTAX
       This section describes the configuration file syntax.

       Whitespace is not significant unless it is within quotes.  This
       provides a wide choice of acceptable indentation styles.  Comments
       begin with # and continue to the end of the line.  They are treated as
       whitespace.

       Here is an informal grammar:

       file = value*
              A configuration file consists of a set of values.

       value = section | assignment
              A value can either be a new section, or an assignment.

       section = identifier '{' value* '}'
              A section is groups associated values together.
              It is denoted by a name and delimited by curly brackets.
              e.g. backup {
                        ...
                   }

       assignment = identifier '=' (array | type)
              An assignment associates a type with an identifier.
              e.g. max_archives = 42

       array = '[' (type ',')* type ']' | '[' ']'
              Inhomogeneous arrays are supported.
              Elements must be separated by commas.
              An empty array is acceptable.

       type = integer | float | string
              integer = [0-9]*
              float = [0-9]*.[0-9]*
              string = '"' .* '"'

              Strings must be enclosed in double quotes.


SECTIONS
       The sections that may be present in the file are:

       devices -- Device settings

              dir -- Directory in which to create volume group device nodes.
              Defaults to "/dev".  Commands also accept this as a prefix on
              volume group names.

              scan -- List of directories to scan recursively for LVM physical
              volumes.  Devices in directories outside this hierarchy will be
              ignored.  Defaults to "/dev".

              preferred_names -- List of patterns compared in turn against all
              the pathnames referencing the same device in in the scanned
              directories.  The pathname that matches the earliest pattern in
              the list is the one used in any output.  As an example, if
              device-mapper multipathing is used, the following will select
              multipath device names:
              devices { preferred_names = [ "^/dev/mapper/mpath" ] }

              filter -- List of patterns to apply to devices found by a scan.
              Patterns are regular expressions delimited by any character and
              preceded by a (for accept) or r (for reject).  The list is
              traversed in order, and the first regex that matches determines
              if the device will be accepted or rejected (ignored).  Devices
              that don't match any patterns are accepted. If you want to
              reject patterns that don't match, end the list with "r/.*/".  If
              there are several names for the same device (e.g. symbolic links
              in /dev), if any name matches any a pattern, the device is
              accepted; otherwise if any name matches any r pattern it is
              rejected; otherwise it is accepted.  As an example, to ignore
              /dev/cdrom you could use:
              devices { filter=["r|cdrom|"] }

              cache_dir -- Persistent filter cache file directory.  Defaults
              to "/etc/lvm/cache".

              write_cache_state -- Set to 0 to disable the writing out of the
              persistent filter cache file when lvm exits.  Defaults to 1.

              types -- List of pairs of additional acceptable block device
              types found in /proc/devices together with maximum (non-zero)
              number of partitions (normally 16).  By default, LVM2 supports
              ide, sd, md, loop, dasd, dac960, nbd, ida, cciss, ubd, ataraid,
              drbd, power2, i2o_block and iseries/vd.  Block devices with
              major numbers of different types are ignored by LVM2.  Example:
              types = ["fd", 16].  To create physical volumes on device-mapper
              volumes created outside LVM2, perhaps encrypted ones from
              cryptsetup, you'll need types = ["device-mapper", 16].  But if
              you do this, be careful to avoid recursion within LVM2.  The
              figure for number of partitions is not currently used in LVM2 -
              and might never be.

              sysfs_scan (em If set to 1 and your kernel supports sysfs and it
              is mounted, sysfs will be used as a quick way of filtering out
              block devices that are not present.

              md_component_detection (em If set to 1, LVM2 will ignore devices
              used as components of software RAID (md) devices by looking for
              md superblocks. This doesn't always work satisfactorily e.g. if
              a device has been reused without wiping the md superblocks
              first.

       log -- Default log settings

              file -- Location of log file.  If this entry is not present, no
              log file is written.

              overwrite -- Set to 1 to overwrite the log file each time a tool
              is invoked.  By default tools append messages to the log file.

              level -- Log level (0-9) of messages to write to the file.  9 is
              the most verbose; 0 should produce no output.

              verbose -- Default level (0-3) of messages sent to stdout or
              stderr.  3 is the most verbose; 0 should produce the least
              output.

              syslog -- Set to 1 (the default) to send log messages through
              syslog.  Turn off by setting to 0.  If you set to an integer
              greater than one, this is used - unvalidated - as the facility.
              The default is LOG_USER.  See /usr/include/sys/syslog.h for safe
              facility values to use.  For example, LOG_LOCAL0 might be 128.

              indent -- When set to 1 (the default) messages are indented
              according to their severity, two spaces per level.  Set to 0 to
              turn off indentation.

              command_names -- When set to 1, the command name is used as a
              prefix for each message.  Default is 0 (off).

              prefix -- Prefix used for all messages (after the command name).
              Default is two spaces.

              activation -- Set to 1 to log messages while devices are
              suspended during activation.  Only set this temporarily while
              debugging a problem because in low memory situations this
              setting can cause your machine to lock up.

       backup -- Configuration for metadata backups.

              archive_dir -- Directory used for automatic metadata archives.
              Backup copies of former metadata for each volume group are
              archived here.  Defaults to "/etc/lvm/archive".

              backup_dir -- Directory used for automatic metadata backups.  A
              single backup copy of the current metadata for each volume group
              is stored here.  Defaults to "/etc/lvm/backup".

              archive -- Whether or not tools automatically archive existing
              metadata into archive_dir before making changes to it.  Default
              is 1 (automatic archives enabled).  Set to 0 to disable.
              Disabling this might make metadata recovery difficult or
              impossible if something goes wrong.

              backup -- Whether or not tools make an automatic backup into
              backup_dir after changing metadata.  Default is 1 (automatic
              backups enabled).  Set to 0 to disable.  Disabling this might
              make metadata recovery difficult or impossible if something goes
              wrong.

              retain_min -- Minimum number of archives to keep.  Defaults to
              10.

              retain_days -- Minimum number of days to keep archive files.
              Defaults to 30.

       shell -- LVM2 built-in readline shell settings

              history_size -- Maximum number of lines of shell history to
              retain (default 100) in $HOME/.lvm_history

       global -- Global settings

              test -- If set to 1, run tools in test mode i.e. no changes to
              the on-disk metadata will get made.  It's equivalent to having
              the -t option on every command.

              activation -- Set to 0 to turn off all communication with the
              device-mapper driver.  Useful if you want to manipulate logical
              volumes while device-mapper is not present in your kernel.

              proc -- Mount point of proc filesystem.  Defaults to /proc.

              umask -- File creation mask for any files and directories
              created.  Interpreted as octal if the first digit is zero.
              Defaults to 077.  Use 022 to allow other users to read the files
              by default.

              format -- The default value of --metadatatype used to determine
              which format of metadata to use when creating new physical
              volumes and volume groups. lvm1 or lvm2.

              fallback_to_lvm1 -- Set this to 1 if you need to be able to
              switch between 2.4 kernels using LVM1 and kernels including
              device-mapper.  The LVM2 tools should be installed as normal and
              the LVM1 tools should be installed with a .lvm1 suffix e.g.
              vgscan.lvm1.  If an LVM2 tool is then run but unable to
              communicate with device-mapper, it will automatically invoke the
              equivalent LVM1 version of the tool.  Note that for LVM1 tools
              to manipulate physical volumes and volume groups created by LVM2
              you must use --metadataformat lvm1 when creating them.

              library_dir -- A directory searched for LVM2's shared libraries
              ahead of the places dlopen (3) searches.

              format_libraries -- A list of shared libraries to load that
              contain code to process different formats of metadata. For
              example, liblvm2formatpool.so is needed to read GFS pool
              metadata if LVM2 was configured --with-pool=shared.

              locking_type -- What type of locking to use.  1 is the default,
              which use flocks on files in locking_dir (see below) to avoid
              conflicting LVM2 commands running concurrently on a single
              machine. 0 disables locking and risks corrupting your metadata.
              If set to 2, the tools will load the external locking_library
              (see below).  If the tools were configured --with-
              cluster=internal (the default) then 3 means to use built-in
              cluster-wide locking.  All changes to logical volumes and their
              states are communicated using locks.

              locking_dir -- The directory LVM2 places its file locks if
              locking_type is set to 1.  The default is /var/lock/lvm.

              locking_library -- The name of the external locking library to
              load if locking_type is set to 2.  The default is
              liblvm2clusterlock.so.  If you need to write such a library,
              look at the lib/locking source code directory.

       tags -- Host tag settings

              hosttags -- If set to 1, create a host tag with the machine
              name.  Setting this to 0 does nothing, neither creating nor
              destroying any tag.  The machine name used is the nodename as
              returned by uname (2).

              Additional host tags to be set can be listed here as
              subsections.  The @ prefix for tags is optional.  Each of these
              host tag subsections can contain a host_list array of host
              names. If any one of these entries matches the machine name
              exactly then the host tag gets defined on this particular host,
              otherwise it doesn't.

              After lvm.conf has been processed, LVM2 works through each host
              tag that has been defined in turn, and if there is a
              configuration file called lvm_<&lt;host_tag>&gt;.conf it attempts to
              load it.  Any settings read in override settings found in
              earlier files.  Any additional host tags defined get appended to
              the search list, so in turn they can lead to further
              configuration files being processed.  Use lvm dumpconfig to
              check the result of config file processing.

              The following example always sets host tags tag1 and sets tag2
              on machines fs1 and fs2:

              tags { tag1 { } tag2 { host_list = [ "fs1", "fs2" ] } }

              These options are useful if you are replicating configuration
              files around a cluster.  Use of hosttags = 1 means every machine
              can have static and identical local configuration files yet use
              different settings and activate different logical volumes by
              default.  See also volume_list below and --addtag in lvm (8).

       activation -- Settings affecting device-mapper activation

              missing_stripe_filler -- When activating an incomplete logical
              volume in partial mode, this option dictates how the missing
              data is replaced.  A value of "error" will cause activation to
              create error mappings for the missing data, meaning that read
              access to missing portions of the volume will result in I/O
              errors. You can instead also use a device path, and in that case
              this device will be used in place of missing stripes. However,
              note that using anything other than "error" with mirrored or
              snapshotted volumes is likely to result in data corruption.  For
              instructions on how to create a device that always returns
              zeros, see lvcreate (8).

              mirror_region_size -- Unit size in KB for copy operations when
              mirroring.

              readahead -- Used when there is no readahead value stored in the
              volume group metadata.  Set to none to disable readahead in
              these circumstances or auto to use the default value chosen by
              the kernel.

              reserved_memory, reserved_stack -- How many KB to reserve for
              LVM2 to use while logical volumes are suspended.  If
              insufficient memory is reserved before suspension, there is a
              risk of machine deadlock.

              process_priority -- The nice value to use while devices are
              suspended.  This is set to a high priority so that logical
              volumes are suspended (with I/O generated by other processes to
              those logical volumes getting queued) for the shortest possible
              time.

              volume_list -- This acts as a filter through which all requests
              to activate a logical volume on this machine are passed.  A
              logical volume is only activated if it matches an item in the
              list.  Tags must be preceded by @ and are checked against all
              tags defined in the logical volume and volume group metadata for
              a match.  @* is short-hand to check every tag set on the host
              machine (see tags above).  Logical volume and volume groups can
              also be included in the list by name e.g. vg00, vg00/lvol1.

       metadata -- Advanced metadata settings

              pvmetadatacopies -- When creating a physical volume using the
              LVM2 metadata format, this is the default number of copies of
              metadata to store on each physical volume.  Currently it can be
              set to 0, 1 or 2.  The default is 1.  If set to 2, one copy is
              placed at the beginning of the disk and the other is placed at
              the end.  It can be overridden on the command line with
              --metadatacopies.  If creating a volume group with just one
              physical volume, it's a good idea to have 2 copies.  If creating
              a large volume group with many physical volumes, you may decide
              that 3 copies of the metadata is sufficient, i.e. setting it to
              1 on three of the physical volumes, and 0 on the rest.  Every
              volume group must contain at least one physical volume with at
              least 1 copy of the metadata (unless using the text files
              described below).  The disadvantage of having lots of copies is
              that every time the tools access the volume group, every copy of
              the metadata has to be accessed, and this slows down the tools.

              pvmetadatasize -- Approximate number of sectors to set aside for
              each copy of the metadata. Volume groups with large numbers of
              physical or logical volumes, or volumes groups containing
              complex logical volume structures will need additional space for
              their metadata.  The metadata areas are treated as circular
              buffers, so unused space becomes filled with an archive of the
              most recent previous versions of the metadata.

              dirs -- List of directories holding live copies of LVM2 metadata
              as text files.  These directories must not be on logical
              volumes.  It is possible to use LVM2 with a couple of
              directories here, preferably on different (non-logical-volume)
              filesystems and with no other on-disk metadata, pvmetadatacopies
              = 0.  Alternatively these directories can be in addition to the
              on-disk metadata areas.  This feature was created during the
              development of the LVM2 metadata before the new on-disk metadata
              areas were designed and no longer gets tested.  It is not
              supported under low-memory conditions, and it is important never
              to edit these metadata files unless you fully understand how
              things work: to make changes you should always use the tools as
              normal, or else vgcfgbackup, edit backup, vgcfgrestore.

FILES
       /etc/lvm/lvm.conf /etc/lvm/archive /etc/lvm/backup
       /etc/lvm/cache/.cache /var/lock/lvm

SEE ALSO
       lvm(8), umask(2), uname(2), dlopen(3), syslog(3), syslog.conf(5)



Sistina Software UK    LVM TOOLS 2.02.44-cvs (02-17-09)            LVM.CONF(5)