lvtab(4)                                                              lvtab(4)


NAME
     lvtab - information about logical volumes

DESCRIPTION
     The file /etc/lvtab describes the logical volumes used by the local
     machine.  There is an entry in this file for every logical volume which
     is used by the system.  This subsystem is no longer supported with the
     current release. The file format description exists in order to
     facilitate conversion to its replacement XLV.

     The file consists of entries which have the form:

          volume_device_name:[volume_name]:[options:]device_pathnames

     For example:

          lv0:logical volume test:stripes=3:devs=/dev/dsk/ips0d1s7, \
          /dev/dsk/ips0d2s7, /dev/dsk/ips0d3s7

     Fields are separated by colons, and lines can be continued by the usual
     backslash convention as illustrated above.  A `#' as the first non-white
     character indicates a comment; blank lines can be present in the file and
     are ignored.

     The fields in each entry have the following significance:

     volume_device_name
          This indicates the names of the special files through which the
          system accesses the logical volume.  In the above example, the entry
          lv0 implies that the logical volume is accessed via the device
          special files /dev/dsk/lv0 and /dev/rdsk/lv0.  Note that volume
          device names are expected to be of the form 'lv' followed by one or
          2 digits; this is enforced by the logical volume utilities.

     volume name
          This is a human-readable identifying name for the logical volume.
          The logical volume labels on the disks constituting a volume also
          carry a copy of the volume name, so utilities are able to check that
          the logical volume on the disks physically present is actually the
          volume expected by /etc/lvtab.

          This field can be null (indicated by a second colon immediately
          following the one terminating the volume_device_name field).  This
          is legal but deprecated, since in this case, no identity check of
          the logical volume can be done by the utilities.

     options
          Some numerical options concerning the volume can appear.  These are
          specified in the format "option_name=number:".  There must be no
          space between the option_name, the '=' sign, the numerical value
          given, and the terminating colon.  Note that since the number of
          options is variable, the terminating colon is considered part of the


          option entry: it is not necessary to indicate omitted options.

          Currently recognized options are:

               stripes=
               step=

          The stripes option allows a striped logical volume to be created;
          the value of the parameter specifies the number of ways the volume
          storage is striped across its constituent devices.  If this option
          is omitted, the logical volume is unstriped.

          The step option is meaningful only for striped volumes (and is
          ignored otherwise); it specifies the granularity with which the
          storage is to be round-robin distributed over the constituent
          devices.  If this option is omitted, the default step value is the
          device tracksize; this is generally a good value so the step option
          is not normally needed.  step is in units of 512-byte blocks.

     device_pathnames
          Following any numerical options, there must be a list of the block
          special file pathnames of the devices constituting the logical
          volume.  This is introduced by the keyword

               devs=

          The pathnames must be comma-separated.

          Each pathname should be the name of the special file for a disk
          device partition in the /dev/dsk directory.  The partition must be
          one which is legal for use as normal data storage--it must not be
          one of the dedicated partitions such as the disk volume label, track
          replacement area, and so on.

          If the volume is striped, some restrictions apply:  the number of
          pathnames must be a multiple of stripes.  Further, considering the
          pathnames as successive groups, each of stripes pathnames, the
          devices in each group must be all of the same size.

          To obtain best performance from striping, each disk (within every
          group of stripes disks) should be on a separate controller.

     The entries from this file are accessed using the program lv_to_xlv(1M),
     which outputs a conversion script to translate between the two formats.
     The file structure is defined in the <lvtab.h> include file.

FILES
     /etc/lvtab


SEE ALSO
     lv_to_xlv(1M),


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