Provided by: lvm2_2.02.66-4ubuntu7_amd64 bug


       lvm.conf - Configuration file for LVM2




       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

       Use lvm dumpconfig to check what settings are in use.


       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.


       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  —  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 — 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.

              md_chunk_alignment  — If set to 1, and a Physical Volume is placed directly upon an
              md device, LVM2 will align its data blocks with the md device's stripe-width.

              data_alignment_detection  —  If  set  to  1,  and  your  kernel  provides  topology
              information  in  sysfs  for  the  Physical  Volume,  the start of data area will be
              aligned on a multiple of the  ’minimum_io_size’  or  ’optimal_io_size’  exposed  in
              sysfs.   minimum_io_size  is  the  smallest  request the device can perform without
              incurring a read-modify-write penalty (e.g. MD's chunk size).   optimal_io_size  is
              the   device's   preferred   unit  of  receiving  I/O  (e.g.  MD's  stripe  width).
              minimum_io_size  is  used  if  optimal_io_size   is   undefined   (0).    If   both
              md_chunk_alignment   and   data_alignment_detection   are  enabled  the  result  of
              data_alignment_detection is used.

              data_alignment — Default alignment (in KB) of start of data area  when  creating  a
              new Physical Volume using the lvm2 format.  If a Physical Volume is placed directly
              upon an md device and md_chunk_alignment  or  data_alignment_detection  is  enabled
              this  parameter  is  ignored.  Set to 0 to use the default alignment of 64KB or the
              page size, if larger.

              data_alignment_offset_detection — If set to 1, and your  kernel  provides  topology
              information in sysfs for the Physical Volume, the start of the aligned data area of
              the Physical Volume will be shifted by the alignment_offset exposed in sysfs.

              To see the location of the first Physical Extent of an existing Physical Volume use
              pvs  -o +pe_start .  It will be a multiple of the requested data_alignment plus the
              alignment_offset from data_alignment_offset_detection (if enabled) or the  pvcreate

       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

              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

              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

              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

       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, 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.  Type 4 enforces read-only metadata and
              forbids  any  operations  that  might  want  to  modify Volume Group metadata.  All
              changes to logical volumes and their states are communicated using locks.

              wait_for_locks — When set to 1, the default, the  tools  wait  if  a  lock  request
              cannot be satisfied immediately.  When set to 0, the operation is aborted instead.

              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  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_<host_tag>.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

              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

              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,

       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,


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


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