1mkfs.gfs2(8) System Manager's Manual mkfs.gfs2(8)
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6 mkfs.gfs2 - create a gfs2 filesystem
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10 mkfs.gfs2 [options] device [block-count]
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14 mkfs.gfs2 is used to create a gfs2 file system.
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18 The default values of the following options have been chosen for best
19 results. In most cases, there should be no need to choose different
20 values. The exceptions to this are the number of journals (-j) and the
21 lock table (-t), as these options will be specific to your cluster.
22 -b bytes
24 Set the filesystem block size to bytes which must be a power of
25 two. The minimum block size is 512 and the block size cannot
26 exceed the machine's memory page size, which on most architec‐
27 tures is 4096 bytes. The default block size is 4096 bytes.
28 -c megabytes
30 Initial size of each journal's quota change file. The default is
31 1MB.
32 -D Enable debugging output.
34 -h Print out a help message describing the available options, then
36 exit.
37 -J megabytes
39 The size of each journal. The minimum size is 8 megabytes and
40 the maximum is 1024. If this is not specified, a value based on
41 a sensible proportion of the file system will be chosen.
42 -j journals
44 The number of journals for mkfs.gfs2 to create. At least one
45 journal is required for each machine that will mount the
46 filesystem concurrently. If this option is not specified, only
47 one journal will be created. This number may be used as an indi‐
48 cator of the number of nodes in the cluster in order to optimize
49 the layout of the filesystem. As such, it is best to set this
50 option with the maximum number of mounters in mind than to add
51 more journals later.
52 -K Do not attempt to discard the block device contents. Issuing
54 discards to the device allows some solid state devices and
55 sparse or thin-provisioned storage devices to optimise free
56 space. Other devices may emulate this behaviour by zeroing the
57 device contents, which can be a slow process.
58 -O Override. This option prevents mkfs.gfs2 from asking for confir‐
60 mation before writing the filesystem.
61 -o Specify extended options. Multiple options can be separated by
63 commas. Valid extended options are:
64 help Display an extended options help summary, then exit.
66 sunit=bytes
68 This is used to specify the stripe unit for a RAID
69 device or striped logical volume. This option ensures
70 that resource groups will be stripe unit aligned and
71 overrides the stripe unit value obtained by probing
72 the device. This value must be a multiple of the file
73 system block size and must be specified with the
74 swidth option.
75 swidth=bytes
77 This is used to specify the stripe width for a RAID
78 device or striped logical volume. This option ensures
79 that resource groups will be stripe aligned and over‐
80 rides the stripe width value obtained by probing the
81 device. This value must be a multiple of the sunit
82 option and must also be specified with it.
83 align=[0|1]
85 Disable or enable the alignment of resource groups.
86 The default behaviour is to align resource groups to
87 the stripe width and stripe unit values obtained from
88 probing the device or specified with the swidth and
89 sunit extended options.
90 -p protocol
92 Specify the locking protocol to use when no locking protocol is
93 specified at mount time. Valid locking protocols are:
94 lock_dlm
96 This is the default. It enables DLM-based locking for
97 use in shared storage configurations.
98 lock_nolock
100 This enables single-node locking
101 -q Quiet mode. Do not print anything.
103 -r megabytes
105 mkfs.gfs2 will try to make resource groups approximately this
106 large. The minimum resource group size is 32 MB and the maximum
107 is 2048 MB. A large resource group size may increase perfor‐
108 mance on very large file systems. If not specified, mkfs.gfs2
109 will choose the resource group size based on the size and align‐
110 ment characteristics of the target device.
111 -t clustername:lockspace
113 The "lock table" pair used to uniquely identify this filesystem
114 in a cluster. The cluster name segment (maximum 32 characters)
115 must match the name given to your cluster in its configuration;
116 only members of this cluster are permitted to use this file sys‐
117 tem. The lockspace segment (maximum 30 characters) is a unique
118 file system name used to distinguish this gfs2 file system.
119 Valid clusternames and lockspaces may only contain alphanumeric
120 characters, hyphens (-) and underscores (_).
121 -V Print program version information, then exit.
123 block-count
125 Use block-count as the size of the filesystem instead of using
126 the whole device. block-count is specified as a number of
127 filesystem blocks.
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130 # mkfs.gfs2 -t mycluster:mygfs2 -p lock_dlm -j 2 /dev/vg0/lv_gfs2
131 This will create a gfs2 filesystem on the block device /dev/vg0/lv_gfs2. It
133 will belong to a cluster named "mycluster" and use the "mygfs2" lock space. It
134 will use DLM for locking and create journals for a two-node cluster.
135 # mkfs.gfs2 -t mycluster:mygfs2 -p lock_nolock -j 3 /dev/vg0/lv_gfs2
137 This will create a filesystem on the block device /dev/vg0/lv_gfs2. It
139 will belong to a cluster named "mycluster" and use the "mygfs2" lockspace, but
140 it will have no cluster locking by default as lock_nolock is used. It will
141 have journals for a three-node cluster.
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144 gfs2(5), gfs2_jadd(8), gfs2_grow(8)
145 mkfs.gfs2(8)