Provided by: ocfs2-tools_1.8.6-1ubuntu1_amd64 bug

NAME

       mkfs.ocfs2 - Creates an OCFS2 file system.

SYNOPSIS

       mkfs.ocfs2  [-b  block-size]  [-C  cluster-size]  [-L  volume-label]  [-M  mount-type] [-N
       number-of-nodes]        [-J         journal-options]         [--fs-features=[no]sparse...]
       [--fs-feature-level=feature-level]    [-T   filesystem-type]   [--cluster-stack=stackname]
       [--cluster-name=clustername] [--global-heartbeat] [--discard | --nodiscard] [-FqvV] device
       [blocks-count]

DESCRIPTION

       mkfs.ocfs2  is  used  to create an OCFS2 file system on a device, usually a partition on a
       shared disk. In order to prevent data loss, mkfs.ocfs2 will not format an  existing  OCFS2
       volume if it detects that it is mounted on another node in the cluster. This tool requires
       the cluster service to be online.

OPTIONS

       -b, --block-size block-size
              Valid block size values are 512, 1K, 2K and 4K bytes per block. If omitted, a value
              will  be  heuristically  determined  based on the expected usage of the file system
              (see the -T option). A block size of 512 bytes is never recommended. Choose 1K,  2K
              or 4K.

       -C, --cluster-size cluster-size
              Valid  cluster  size  values are 4K, 8K, 16K, 32K, 64K, 128K, 256K, 512K and 1M. If
              omitted, a value will be heuristically determined based on the  expected  usage  of
              the  file  system  (see  the -T option). For volumes expected to store large files,
              like database files, while a cluster size of 128K or more is recommended,  one  can
              opt for a smaller size as long as that value is not smaller than the database block
              size.  For others, use 4K.

       -F, --force
              For existing OCFS2 volumes, mkfs.ocfs2 ensures the volume is  not  mounted  on  any
              node  in  the  cluster  before formatting. For that to work, mkfs.ocfs2 expects the
              cluster service to be online.  Specify this option to disable this check.

       -J, --journal-options options
              Create the journal using options specified on the command-line. Journal options are
              comma  separated,  and  may  take  an  argument  using  the  equals ('=') sign. The
              following options are supported:

              size=journal-size
                     Create a journal of size journal-size. Minimum size is 4M.   If  omitted,  a
                     value is heuristically determined based upon the file system size.

              block32
                     Use  a  standard  32bit  journal.   The journal will be able to access up to
                     2^32-1 blocks.  This is the default.  It has been  the  journal  format  for
                     OCFS2  volumes  since  the  beginning.   The  journal is compatible with all
                     versions of OCFS2.  Prepending no  is  equivalent  to  the  block64  journal
                     option.

              block64
                     Use  a  64bit  journal.   The  journal  will  be able to access up to 2^64-1
                     blocks.  This allows large filesystems that can extend  to  the  theoretical
                     limits  of  OCFS2.  It requires a new-enough filesystem driver that uses the
                     new journalled block device,  JBD2.  Prepending  no  is  equivalent  to  the
                     block32 journal option.

       -L, --label volume-label
              Set  the  volume  label  for the file system. This is useful for mounting-by-label.
              Limit the label to under 64 bytes.

       -M, --mount mount-type
              Valid types are local and cluster. Local mount allows users  to  mount  the  volume
              without  the  cluster overhead and works only with OCFS2 bundled with Linux kernels
              2.6.20 or later. Defaults to cluster.

       -N, --node-slots number-of-node-slots
              Valid number ranges from 1 to 255. This number  specifies  the  maximum  number  of
              nodes  that can concurrently mount the partition. If omitted, the number depends on
              volume size, for volume size < 2G, it's 2, for 2G <= size < 10G, it's 4, for 10G <=
              size  < 1T, it's 8, for other size, it's 16. The number of slots can be later tuned
              up or down using tunefs.ocfs2.

       -T filesystem-type
              Specify how the filesystem is going to  be  used,  so  that  mkfs.ocfs2  can  chose
              optimal filesystem parameters for that use. The supported filesystem types are:

              mail   Appropriate for file systems that will host lots of small files.

              datafiles
                     Appropriate  for  file  systems  that will host a relatively small number of
                     very large files.

              vmstore
                     Appropriate for file systems that will host Virtual machine images.

       --fs-features=[no]sparse...
              Turn specific file system features on or off. A comma  separated  list  of  feature
              flags can be provided, and mkfs.ocfs2 will try to create the file system with those
              features set according to the list. To turn a feature on, include it in  the  list.
              To  turn  a  feature  off,  prepend  no  to  the  name.  Choices here will override
              individual features set via the --fs-feature-level option.  Refer  to  the  section
              titled  feature  compatibility  before  selecting  specific features. The following
              flags are supported:

              backup-super
                     mkfs.ocfs2, by default, makes up to 6 backup copies of the  super  block  at
                     offsets  1G,  4G, 16G, 64G, 256G and 1T depending on the size of the volume.
                     This can be useful in disaster recovery. This feature  is  fully  compatible
                     with all versions of the file system and generally should not be disabled.

              local  Create the file system as a local mount, so that it can be mounted without a
                     cluster stack.

              sparse Enable support for sparse files. With this, OCFS2 can avoid allocating  (and
                     zeroing)  data  to  fill  holes.  Turn this feature on if you can, otherwise
                     extends and some writes might be less performant.

              unwritten
                     Enable unwritten extents support. With this turned on,  an  application  can
                     request  that a range of clusters be pre-allocated within a file. OCFS2 will
                     mark those extents with a  special  flag  so  that  expensive  data  zeroing
                     doesn't have to be performed. Reads and writes to a pre-allocated region act
                     as reads and writes to a hole, except a write will not fail due to  lack  of
                     data allocation. This feature requires sparse file support to be turned on.

              inline-data
                     Enable  inline-data  support. If this feature is turned on, OCFS2 will store
                     small files and directories inside the inode block.  Data  is  transparently
                     moved  out  to  an  extent when it no longer fits inside the inode block. In
                     some cases, this can also make a positive impact on cold-cache directory and
                     file operations.

              extended-slotmap
                     The  slot-map  is  a hidden file on an OCFS2 fs which is used to map mounted
                     nodes to system file resources. The extended slot map allows a larger  range
                     of  possible  node numbers, which is useful for userspace cluster stacks. If
                     required, this feature is automatically turned on by mkfs.ocfs2.

              metaecc
                     Enables metadata checksums. With this enabled, the file system computes  and
                     stores  the checksums in all metadata blocks. It also computes and stores an
                     error correction code capable of fixing single bit errors.

              refcount
                     Enables creation of reference counted trees. With  this  enabled,  the  file
                     system  allows  users  to  create  inode-based snapshots and clones known as
                     reflinks.

              xattr  Enable extended attributes support. With  this  enabled,  users  can  attach
                     name:value  pairs to objects within the file system. In OCFS2, the names can
                     be up to 255 bytes in length, terminated by the first NUL byte. While it  is
                     not  required, printable names (ASCII) are recommended. The values can be up
                     to 64KB of arbitrary binary data. Attributes can be attached to all types of
                     inodes:  regular files, directories, symbolic links, device nodes, etc. This
                     feature is required for users wanting to use  extended  security  facilities
                     like POSIX ACLs or SELinux.

              usrquota
                     Enable  user quota support. With this feature enabled, filesystem will track
                     amount of space and number of inodes (files,  directories,  symbolic  links)
                     each  user owns. It is then possible to limit the maximum amount of space or
                     inodes user can have. See a documentation of quota-tools  package  for  more
                     details.

              grpquota
                     Enable group quota support. With this feature enabled, filesystem will track
                     amount of space and number of inodes (files,  directories,  symbolic  links)
                     each group owns. It is then possible to limit the maximum amount of space or
                     inodes user can have. See a documentation of quota-tools  package  for  more
                     details.

              indexed-dirs
                     Enable  directory  indexing  support.  With  this  feature enabled, the file
                     system creates indexed tree for  non-inline  directory  entries.  For  large
                     scale  directories, directory entry lookup performance from the indexed tree
                     is faster then from the legacy directory blocks.

              discontig-bg
                     Enables discontiguous block groups. With  this  feature  enabled,  the  file
                     system  is  able to grow the inode and the extent allocators even when there
                     is no contiguous free chunk available. It allows the file system to grow the
                     allocators in smaller (discontiguous) chunks.

              clusterinfo
                     Enables  storing  the  cluster  stack  information  in  the superblock. This
                     feature is needed  to  support  userspace  cluster  stacks  and  the  global
                     heartbeat  mode  in  the  o2cb  cluster  stack.  If  needed, this feature is
                     automatically turned on by mkfs.ocfs2.

       --fs-feature-level=feature-level
              Choose from a set of pre-determined file-system features. This option  is  designed
              to  allow  users  to  conveniently  choose a set of file system features which fits
              their needs. There is no downside to trying a set of  features  which  your  module
              might  not  support  -  if  it won't mount the new file system simply reformat at a
              lower level. Feature  levels  can  be  fine-tuned  via  the  --fs-features  option.
              Currently, there are 3 types of feature levels:

              max-compat
                     Chooses  fewer features but ensures that the file system can be mounted from
                     older versions of the OCFS2 module.

              default
                     The default feature set tries to strike  a  balance  between  providing  new
                     features  and  maintaining  compatibility with relatively recent versions of
                     OCFS2. It currently enables sparse, unwritten, inline-data, xattr,  indexed-
                     dirs, discontig-bg, refcount, extended-slotmap and clusterinfo.

              max-features
                     Choose the maximum amount of features available. This will typically provide
                     the best performance from OCFS2 at the expense of  creating  a  file  system
                     that  is  only  compatible  with  very  recent  versions of the OCFS2 kernel
                     module.

       --cluster-stack
              Specify the cluster stack. This option  is  normally  not  required  as  mkfs.ocfs2
              chooses  the  currently  active  cluster  stack. It is required only if the cluster
              stack is not online and the user wishes to use a  stack  other  than  the  default,
              o2cb.  Other  supported  cluster  stacks are pcmk (Pacemaker) and cman (rgmanager).
              Once set, OCFS2 will only allow mounting the volume if the active cluster stack and
              cluster name matches the one specified on-disk.

       --cluster-name
              Specify the name of the cluster. This option is mandatory if the user has specified
              a cluster-stack. This name is restricted to a max of 16  characters.  Additionally,
              the o2cb cluster stack allows only alpha-numeric characters.

       --global-heartbeat
              Enable  the  global  heartbeat  mode  of the o2cb cluster stack. This option is not
              required if the o2cb cluster stack with global heartbeat is  online  as  mkfs.ocfs2
              will  detect  the  active stack. However, if the cluster stack is not up, then this
              option is required alongwith cluster-stack and cluster-name.  For  more,  refer  to
              o2cb(7).

       --discard
              Attempt  to  discard  blocks at mkfs time (discarding blocks initially is useful on
              solid state devices  and  sparse  /  thin-provisioned  storage).  When  the  device
              advertises that discard also zeroes data (any subsequent read after the discard and
              before write returns zero), then mark all not-yet-zeroed  blocks  as  zeroed.  This
              significantly speeds up filesystem initialization. This is set as default.

       --nodiscard
              Do not attempt to discard blocks at mkfs time.

       --no-backup-super
              This option is deprecated, please use --fs-features=nobackup-super instead.

       -n, --dry-run
              Display  the  heuristically determined values without overwriting the existing file
              system.

       -q, --quiet
              Quiet mode.

       -U uuid
              Specify  a  custom  UUID  in  the   plain   (2A4D1C581FAA42A1A41D26EFC90C1315)   or
              traditional  (2a4d1c58-1faa-42a1-a41d-26efc90c1315)  format.  This  option  in  not
              recommended because the file system uses the  UUID  to  uniquely  identify  a  file
              system. If more than one file system were to have the same UUID, one is very likely
              to encounter erratic behavior, if not, outright file system corruption.

       -v, --verbose
              Verbose mode.

       -V, --version
              Print version and exit.

       blocks-count
              Usually mkfs.ocfs2 automatically determines  the  size  of  the  given  device  and
              creates  a  file  system  that uses all of the available space on the device.  This
              optional argument specifies that the file system  should  only  consume  the  given
              number of file system blocks (see -b) on the device.

FEATURE COMPATIBILITY

       This  section lists the file system features that have been added to the OCFS2 file system
       and the version that it first appeared in. The table  below  lists  the  versions  of  the
       mainline  Linux  kernel  and ocfs2-tools. Users should use this information to enable only
       those features that are available in the file system that they are using.  Before enabling
       new features, users are advised to review to the section titled feature values.

                         ┌─────────────────┬────────────────┬─────────────────┐
                         │FeatureKernel VersionTools Version   │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │local            │  Linux 2.6.20  │ ocfs2-tools 1.2 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │sparse           │  Linux 2.6.22  │ ocfs2-tools 1.4 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │unwritten        │  Linux 2.6.23  │ ocfs2-tools 1.4 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │inline-data      │  Linux 2.6.24  │ ocfs2-tools 1.4 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │extended-slotmap │  Linux 2.6.27  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │metaecc          │  Linux 2.6.29  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │grpquota         │  Linux 2.6.29  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │usrquota         │  Linux 2.6.29  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │xattr            │  Linux 2.6.29  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │indexed-dirs     │  Linux 2.6.30  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │refcount         │  Linux 2.6.32  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │discontig-bg     │  Linux 2.6.35  │ ocfs2-tools 1.6 │
                         ├─────────────────┼────────────────┼─────────────────┤
                         │clusterinfo      │  Linux 2.6.37  │ ocfs2-tools 1.8 │
                         └─────────────────┴────────────────┴─────────────────┘

       Users can query the features enabled in the file system as follows:

       # tunefs.ocfs2 -Q "Label: %V\nFeatures: %H %O\n" /dev/sdg1
       Label: apache_files_10
       Features: sparse inline-data unwritten

FEATURE VALUES

       This section lists the hex values that are associated with the file system features.  This
       information  is  useful  when  debugging  mount  failures  that   are   due   to   feature
       incompatibility.  When  a user attempts to mount an OCFS2 volume that has features enabled
       that are not supported by the running file system software, it will  fail  with  an  error
       like:

       ERROR: couldn't mount because of unsupported optional features (200).

       By  referring  to  the table below, it becomes apparent that the user attempted to mount a
       volume with the xattr (extended attributes) feature enabled with a  version  of  the  file
       system  software that did not support it. At this stage, the user has the option of either
       upgrading the file system software, or, disabling that on-disk feature using tunefs.ocfs2.

       Some features allow the file system to be mounted with an older version  of  the  software
       provided the mount is read-only. If a user attempts to mount such a volume in a read-write
       mode, it will fail with an error like:

       ERROR: couldn't mount RDWR because of unsupported optional features (1).

       This error indicates that the volume had the unwritten RO compat  feature  enabled.   This
       volume  can  be  mounted  by an older file system software only in the read-only mode.  In
       this case, the user has the option of either mounting the volume with the ro mount option,
       or, disabling that on-disk feature using tunefs.ocfs2.

                               ┌─────────────────┬───────────┬───────────┐
                               │FeatureCategoryHex value │
                               ├─────────────────┼───────────┼───────────┤
                               │local            │ Incompat  │     8     │
                               ├─────────────────┼───────────┼───────────┤
                               │sparse           │ Incompat  │    10     │
                               ├─────────────────┼───────────┼───────────┤
                               │inline-data      │ Incompat  │    40     │
                               ├─────────────────┼───────────┼───────────┤
                               │extended-slotmap │ Incompat  │    100    │
                               ├─────────────────┼───────────┼───────────┤
                               │xattr            │ Incompat  │    200    │
                               ├─────────────────┼───────────┼───────────┤
                               │indexed-dirs     │ Incompat  │    400    │
                               ├─────────────────┼───────────┼───────────┤
                               │metaecc          │ Incompat  │    800    │
                               ├─────────────────┼───────────┼───────────┤
                               │refcount         │ Incompat  │   1000    │
                               ├─────────────────┼───────────┼───────────┤
                               │discontig-bg     │ Incompat  │   2000    │
                               ├─────────────────┼───────────┼───────────┤
                               │clusterinfo      │ Incompat  │   4000    │
                               ├─────────────────┼───────────┼───────────┤
                               │unwritten        │ RO Compat │     1     │
                               ├─────────────────┼───────────┼───────────┤
                               │usrquota         │ RO Compat │     2     │
                               ├─────────────────┼───────────┼───────────┤
                               │grpquota         │ RO Compat │     4     │
                               └─────────────────┴───────────┴───────────┘

SEE ALSO

       debugfs.ocfs2(8)   fsck.ocfs2(8)   mount.ocfs2(8)  mounted.ocfs2(8)  o2cb(7)  o2cluster(8)
       o2image(8) o2info(1) tunefs.ocfs2(8)

AUTHORS

       Oracle Corporation

COPYRIGHT

       Copyright © 2004, 2012 Oracle. All rights reserved.