Provided by: gnbd-server_1.20060222-0ubuntu5_i386 bug


       gnbd_export - the interface to export GNBDs


       gnbd_export [OPTION]...


       gnbd_export exports local block devices or files as GNBDs.


       -a     Validate.

              This  option  forces all server processes to send a ping message
              to the clients they are connected to. This forces  servers  with
              faulty connections to quit.

       -c     Enable caching.

              Reads  from  the  exported GNBD will take advantage of the linux
              page cache.  This option is used with -e. NOTE: If  this  option
              is  not  specified,  gnbd will run with a noticeable performance
              decrease.  Also, if this option is not specified,  the  exported
              GNBD will run in timeout mode, with the default timeout (see the
              -t option).  With the -c option, it is not necessary to have the
              gnbd server machine be part of the cluster.  If -c option is not
              used, the server machine must already  have  a  cluster  manager
              running  on  it.  When  the first uncached gnbd is exported, the
              gnbd_clusterd daemon will be started. This  daemon  connects  to
              the  cluster manager via the magma interface.  WARNING: You must
              NOT specify this  option  if  you  wish  to  use  gnbd  with  dm
              multipathing,  or run GFS on gnbd server machines.  To set up dm
              multipathing over gnbd, all gnbds involved must run with caching
              disabled.   Data  corruption  will occur if the GNBD devices are
              run with caching. Any device that is  exported  without  the  -c
              option  can also be used locally, but you must access the device
              directly.  You  MUST  NOT  use  gnbd_import  to  import  devices
              exported from the same machine.

       -d pathname

              Specify  the  device  to  export as a GNBD.  This option is used
              with -e.  pathname may be either a block  device  or  a  regular
              file.   Usually  block  devices are used, because this increases
              GNBD performance.

       -e gnbdname

              Export a device as a GNBD with the  Device  name  gnbdname.  You
              must also specify the pathname of the device with the -d option.
              Once a GNBD has  been  exported,  clients  can  import  it  with

       -h     Help.

              Print the usage information.

       -l     List.

              List all exported GNBDs and kgnbd_portd server information.  The
              listing  contains  each  server’s  number  (which  is  only  for
              internal  use), its Device name, the pathname of the device that
              is  being  exported,  it’s  size  in  512  byte   sectors,   and
              information  on  whether  or  not it is cached, and if not, what
              it’s timeout is.

       -O     Override

              This option allows you to unexport gnbd devices,  even  if  they
              are  still  in use.  When an agent other than fence_gnbd is used
              to fence gnbd client nodes, occasionally gnbd server threads are
              not  correctly  cleaned  up.  This causes no performance issues.
              However, the affected gnbd devices  cannot  be  unexported.   In
              this  case,  using the -O option with either -r or -R will allow
              you to unexport the GNBD devices.  WARNING: Make  sure  that  no
              clients have the GNBD imported before using this option.

       -o     Readonly

              export the server in readonly mode.

       -q     Quiet.

              Only prints out error messages.

       -R     Remove All.

              Remove all exported GNBDs.

       -r [GNBD(s)]

              Remove named GNBD(s).

       -t [seconds]

              Set  the exported GNBD to timeout mode  This option is used with
              -p.  This is the default for uncached GNBDs. For  cached  GNBDs,
              the  default  is wait mode (For GFS versions up through 5.2, all
              GNBDs were in wait mode).  In wait mode, if  the  connection  to
              the  server is lost, the gnbd client waits for the connection to
              be reestablished, and then resends all the pending requests.  In
              timeout  mode,  if  the connection cannot be reestablished or if
              the gnbd client does not receive  a  response  from  the  server
              within  the  timeout period, the gnbd client returns all pending
              and future requests as  failures  until  the  imported  GNBD  is
              closed.  The  default timeout period is 60 seconds. Timeout mode
              is necessary for failover to  work  with  dm  multipathing  over

       -v     Verbose.

              Increase  the  verbosity of the output.  This option is the most
              useful with -l.  If it is used along with -l, an  extended  list
              of information on each exported device will be printed.

       -V     Version information.

              Print out version information.


       gnbd_import(8), gnbd(8)