Provided by: gfs2-utils_3.5.0-2_amd64 
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.
format=<number>
Set the filesystem format version. Testing only.
-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
(_).
-U UUID
Specify the filesystem UUID. The argument must be string of hexadecimal digits
separated by hyphens, of the form "1b4e28ba-2fa1-11d2-883f-b9a761bde3fb". If this
option is omitted, the filesystem's UUID is randomly generated. Note that no
attempt is made to prevent UUID clashes between filesystems.
-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)