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)