Provided by: gfs2-utils_3.2.0-2_amd64 bug

NAME

       mkfs.gfs2 - create a gfs2 filesystem

SYNOPSIS

       mkfs.gfs2 [options] device [block-count]

DESCRIPTION

       mkfs.gfs2 is used to create a gfs2 file system.

OPTIONS

       The  default  values  of the following options have been chosen for best results.  In most
       cases, there should be no need to choose different values. The exceptions to this are  the
       number of journals (-j) and the lock table (-t), as these options will be specific to your
       cluster.

       -b bytes
              Set the filesystem block size to bytes which must be a power of  two.  The  minimum
              block  size is 512 and the block size cannot exceed the machine's memory page size,
              which on most architectures is 4096 bytes.  The default block size is 4096 bytes.

       -c megabytes
              Initial size of each journal's quota change file. The default is 1MB.

       -D     Enable debugging output.

       -h     Print out a help message describing the available options, then exit.

       -J megabytes
              The size of each journal. The minimum size is 8 megabytes and the maximum is  1024.
              If this is not specified, a value based on a sensible proportion of the file system
              will be chosen.

       -j journals
              The number of journals for mkfs.gfs2 to create.  At least one journal  is  required
              for  each  machine  that will mount the filesystem concurrently.  If this option is
              not specified, only one journal will be created. This number  may  be  used  as  an
              indicator  of the number of nodes in the cluster in order to optimize the layout of
              the filesystem. As such, it is best to set this option with the maximum  number  of
              mounters in mind than to add more journals later.

       -K     Do not attempt to discard the block device contents. Issuing discards to the device
              allows some solid state devices and sparse or thin-provisioned storage  devices  to
              optimise free space. Other devices may emulate this behaviour by zeroing the device
              contents, which can be a slow process.

       -O     Override. This option  prevents  mkfs.gfs2  from  asking  for  confirmation  before
              writing the filesystem.

       -o     Specify  extended  options.  Multiple  options  can  be  separated by commas. Valid
              extended options are:

                 help   Display an extended options help summary, then exit.

                 sunit=bytes
                        This is used to specify the stripe unit for  a  RAID  device  or  striped
                        logical  volume.  This option ensures that resource groups will be stripe
                        unit aligned and overrides the stripe unit value obtained by probing  the
                        device.  This  value must be a multiple of the file system block size and
                        must be specified with the swidth option.

                 swidth=bytes
                        This is used to specify the stripe width for a  RAID  device  or  striped
                        logical  volume.  This option ensures that resource groups will be stripe
                        aligned and overrides the stripe width  value  obtained  by  probing  the
                        device.  This  value must be a multiple of the sunit option and must also
                        be specified with it.

                 align=[0|1]
                        Disable or enable the alignment of resource groups. The default behaviour
                        is  to  align  resource groups to the stripe width and stripe unit values
                        obtained from probing the device or specified with the swidth  and  sunit
                        extended options.

       -p protocol
              Specify  the locking protocol to use when no locking protocol is specified at mount
              time. Valid locking protocols are:

                 lock_dlm
                        This is the default. It enables  DLM-based  locking  for  use  in  shared
                        storage configurations.

                 lock_nolock
                        This enables single-node locking

       -q     Quiet mode. Do not print anything.

       -r megabytes
              mkfs.gfs2  will  try to make resource groups approximately this large.  The minimum
              resource group size is 32 MB and the maximum is 2048 MB.  A  large  resource  group
              size  may  increase  performance  on  very  large  file systems.  If not specified,
              mkfs.gfs2 will choose the resource group size  based  on  the  size  and  alignment
              characteristics of the target device.

       -t clustername:lockspace
              The  "lock table" pair used to uniquely identify this filesystem in a cluster.  The
              cluster name segment (maximum 32 characters) must match  the  name  given  to  your
              cluster  in  its  configuration;  only members of this cluster are permitted to use
              this file system.  The lockspace segment (maximum 30 characters) is a  unique  file
              system  name  used  to  distinguish  this gfs2 file system.  Valid clusternames and
              lockspaces may only contain alphanumeric characters, hyphens  (-)  and  underscores
              (_).

       -V     Print program version information, then exit.

       block-count
              Use  block-count  as  the size of the filesystem instead of using the whole device.
              block-count is specified as a number of filesystem blocks.

EXAMPLE

              # mkfs.gfs2 -t mycluster:mygfs2 -p lock_dlm -j 2 /dev/vg0/lv_gfs2

              This will create a gfs2 filesystem on the block device /dev/vg0/lv_gfs2.  It
              will belong to a cluster named "mycluster" and use the "mygfs2" lock space.  It
              will use DLM for locking and create journals for a two-node cluster.

              # mkfs.gfs2 -t mycluster:mygfs2 -p lock_nolock -j 3 /dev/vg0/lv_gfs2

              This will create a filesystem on the block device /dev/vg0/lv_gfs2.  It
              will belong to a cluster named "mycluster" and use the "mygfs2" lockspace, but
              it will have no cluster locking by default as lock_nolock is used.  It will
              have journals for a three-node cluster.

SEE ALSO

       gfs2(5), gfs2_jadd(8), gfs2_grow(8)

                                                                                     mkfs.gfs2(8)