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HAST.CONF(5)		       File Formats Manual		    HAST.CONF(5)

NAME
     hast.conf	-- configuration file for the hastd(8) deamon and the hastctl(8)
     utility.

DESCRIPTION
     The hast.conf file is used by both hastd(8) daemon and  hastctl(8)  control
     utility.	Configuration  file  is  designed in a way that exactly the same
     file can be (and should be) used on both HAST nodes.  Every  line	starting
     with # is treated as comment and ignored.

CONFIGURATION FILE SYNTAX
     General syntax of the hast.conf file is following:

	   # Global section
	   control <addr>
	   listen <addr>
	   replication <mode>
	   timeout <seconds>

	   on <node> {
		   # Node section
		   control <addr>
		   listen <addr>
	   }

	   on <node> {
		   # Node section
		   control <addr>
		   listen <addr>
	   }

	   resource <name> {
		   # Resource section
		   replication <mode>
		   name <name>
		   local <path>
		   timeout <seconds>

		   on <node> {
			   # Resource-node section
			   name <name>
			   # Required
			   local <path>
			   # Required
			   remote <addr>
		   }
		   on <node> {
			   # Resource-node section
			   name <name>
			   # Required
			   local <path>
			   # Required
			   remote <addr>
		   }
	   }

     Most  of  the  various available configuration parameters are optional.  If
     parameter is not defined in the particular section, it  will  be  inherited
     from  the	parent section.  For example, if the listen parameter is not de-
     fined in the node section, it will be inherited from  the	global	section.
     In case the global section does not define the listen parameter at all, the
     default value will be used.

CONFIGURATION FILE DESCRIPTION
     The  <node>  argument can be replaced either by a full hostname as obtained
     by gethostname(3), only first part of the hostname, or by	node's	UUID  as
     found in the kern.hostuuid sysctl(8) variable.

     The following statements are available:

     control <addr>

	   Address for communication with hastctl(8).  Each of the following ex-
	   amples defines the same control address:

		 uds:///var/run/hastctl
		 unix:///var/run/hastctl
		 /var/run/hastctl

	   The default value is uds:///var/run/hastctl.

     listen <addr>

	   Address to listen on in form of:

		 protocol://protocol-specific-address

	   Each of the following examples defines the same listen address:

		 0.0.0.0
		 0.0.0.0:8457
		 tcp://0.0.0.0
		 tcp://0.0.0.0:8457
		 tcp4://0.0.0.0
		 tcp4://0.0.0.0:8457

	   The default value is tcp4://0.0.0.0:8457.

     replication <mode>

	   Replication mode should be one of the following:

	   memsync

		 Report  the  write operation as completed when local write com-
		 pletes and when the remote node acknowledges the data	receipt,
		 but  before  it  actually  stores the data.  The data on remote
		 node will be stored  directly	after  sending	acknowledgement.
		 This  mode  is intended to reduce latency, but still provides a
		 very good reliability.  The only  situation  where  some  small
		 amount of data could be lost is when the data is stored on pri-
		 mary  node  and sent to the secondary.  Secondary node then ac-
		 knowledges data receipt and primary reports success to  an  ap-
		 plication.   However,	it  may  happen that the seconderay goes
		 down before the received data is really stored locally.  Before
		 secondary node returns, primary node dies entirely.   When  the
		 secondary  node  comes back to life it becomes the new primary.
		 Unfortunately some small amount of data which was confirmed  to
		 be stored to the application was lost.  The risk of such a sit-
		 uation  is  very small, which is the reason for this mode to be
		 the default.

	   fullsync

		 Mark the write operation as completed when local as well as re-
		 mote write completes.	This  is  the  safest  and  the  slowest
		 replication  mode.   The fullsync replication mode is currently
		 not implemented.

	   async

		 The write operation is reported as complete right after the lo-
		 cal write completes.  This is the fastest and the most  danger-
		 ous  replication mode.  This mode should be used when replicat-
		 ing to a distant node where  latency  is  too	high  for  other
		 modes.   The  async  replication  mode  is currently not imple-
		 mented.

     timeout <seconds>

	   Connection timeout in seconds.  The default value is 5.

     name <name>

	   GEOM provider name that will appear as /dev/hast/<name>.  If name  is
	   not defined, resource name will be used as provider name.

     local <path>

	   Path  to  the  local component which will be used as backend provider
	   for the resource.  This can be either GEOM provider or regular file.

     remote <addr>

	   Address of the remote hastd daemon.	Format is the same  as	for  the
	   listen statement.  When operating as a primary node this address will
	   be  used  to connect to the secondary node.	When operating as a sec-
	   ondary node only connections from this address will be accepted.

EXAMPLES
     The example configuration file can look as follows:

	   resource shared {
		   local /dev/da0

		   on hasta {
			   remote tcp4://10.0.0.2
		   }
		   on hastb {
			   remote tcp4://10.0.0.1
		   }
	   }
	   resource tank {
		   on hasta {
			   local /dev/mirror/tanka
			   remote tcp4://10.0.0.2
		   }
		   on hastb {
			   local /dev/mirror/tankb
			   remote tcp4://10.0.0.1
		   }
	   }

FILES
     /etc/hast.conf    The default hast.conf configuration file.
     /var/run/hastctl  Control socket used by the hastctl(8) control utility  to
		       communicate with the hastd(8) daemon.

SEE ALSO
     gethostname(3), geom(4), hastctl(8), hastd(8).

AUTHORS
     The  hast.conf  was  written by Pawel Jakub Dawidek <pjd@FreeBSD.org> under
     sponsorship of the FreeBSD Foundation.

FreeBSD 8.1			February 1, 2010		    HAST.CONF(5)
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