NAME

       cephfs - ceph file system options utility

SYNOPSIS

       cephfs [ path command options ]

DESCRIPTION

       cephfs  is  a  control  utility  for accessing and manipulating file layout and location data in the Ceph
       distributed storage system.

       Choose one of the following three commands:

       • show_layout View the layout information on a file or directory

       • set_layout Set the layout information on a file or directory

       • show_location View the location information on a file

OPTIONS

       Your applicable options differ depending on whether you are setting or viewing layout/location.

   Viewing options:
       -l --offset
              Specify an offset for which to retrieve location data

   Setting options:
       -u --stripe_unit
              Set the size of each stripe

       -c --stripe_count
              Set the number of objects to stripe across

       -s --object_size
              Set the size of the objects to stripe across

       -p --pool
              Set the pool (by numeric value, not name!) to use

       -o --osd
              Set the preferred OSD to use as the primary (deprecated and ignored)

LIMITATIONS

       When setting layout data, the specified object size must evenly divide by the specified stripe unit.  Any
       parameters you don't set explicitly are left at the system defaults.

       Obviously  setting  the  layout of a file and a directory means different things. Setting the layout of a
       file specifies exactly how to place the individual file. This must be done before writing any data to it.
       Truncating a file does not allow you to change the layout either.

       Setting the layout of a directory sets the "default layout", which is used to set the file layouts on any
       files subsequently created in the directory (or any subdirectory).  Pre-existing files do not have  their
       layouts changed.

       You'll  notice  that  the  layout  information  allows you to specify a preferred OSD for placement. This
       feature is unsupported and ignored in modern versions of the Ceph servers; do not use it.

AVAILABILITY

       cephfs is part of Ceph, a massively scalable, open-source, distributed storage system.  Please  refer  to
       the Ceph documentation at http://ceph.com/docs for more information.

SEE ALSO

       ceph(8)

COPYRIGHT

       2010-2014,  Inktank  Storage,  Inc.  and  contributors. Licensed under Creative Commons Attribution Share
       Alike 3.0 (CC-BY-SA-3.0)

dev                                            September 09, 2020                                      CEPHFS(8)