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2 .\" Copyright (c) 2010-2012 Pawel Jakub Dawidek <pawel@dawidek.net>
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36 .Nd configuration file for the
50 Configuration file is designed in a way that exactly the same file can be
51 (and should be) used on both HAST nodes.
52 Every line starting with # is treated as comment and ignored.
53 .Sh CONFIGURATION FILE SYNTAX
57 .Bd -literal -offset indent
63 compression <algorithm>
87 compression <algorithm>
95 # Resource-node section
105 # Resource-node section
117 Most of the various available configuration parameters are optional.
118 If parameter is not defined in the particular section, it will be
119 inherited from the parent section.
122 parameter is not defined in the node section, it will be inherited from
124 In case the global section does not define the
126 parameter at all, the default value will be used.
127 .Sh CONFIGURATION FILE DESCRIPTION
130 argument can be replaced either by a full hostname as obtained by
132 only first part of the hostname, by node's UUID as found in the
136 or by node's hostid as found in the
141 The following statements are available:
142 .Bl -tag -width ".Ic xxxx"
143 .It Ic control Aq addr
145 Address for communication with
147 Each of the following examples defines the same control address:
148 .Bd -literal -offset indent
149 uds:///var/run/hastctl
150 unix:///var/run/hastctl
155 .Pa uds:///var/run/hastctl .
156 .It Ic pidfile Aq path
158 File in which to store the process ID of the main
163 .Pa /var/run/hastd.pid .
164 .It Ic listen Aq addr
166 Address to listen on in form of:
167 .Bd -literal -offset indent
168 protocol://protocol-specific-address
171 Each of the following examples defines the same listen address:
172 .Bd -literal -offset indent
181 Multiple listen addresses can be specified.
185 .Pa tcp4://0.0.0.0:8457
188 if kernel supports IPv4 and IPv6 respectively.
189 .It Ic replication Aq mode
191 Replication mode should be one of the following:
192 .Bl -tag -width ".Ic xxxx"
195 Report the write operation as completed when local write completes and
196 when the remote node acknowledges the data receipt, but before it
197 actually stores the data.
198 The data on remote node will be stored directly after sending
200 This mode is intended to reduce latency, but still provides a very good
202 The only situation where some small amount of data could be lost is when
203 the data is stored on primary node and sent to the secondary.
204 Secondary node then acknowledges data receipt and primary reports
205 success to an application.
206 However, it may happen that the secondary goes down before the received
207 data is really stored locally.
208 Before secondary node returns, primary node dies entirely.
209 When the secondary node comes back to life it becomes the new primary.
210 Unfortunately some small amount of data which was confirmed to be stored
211 to the application was lost.
212 The risk of such a situation is very small.
215 replication mode is the default.
218 Mark the write operation as completed when local as well as remote
220 This is the safest and the slowest replication mode.
223 The write operation is reported as complete right after the local write
225 This is the fastest and the most dangerous replication mode.
226 This mode should be used when replicating to a distant node where
227 latency is too high for other modes.
229 .It Ic checksum Aq algorithm
231 Checksum algorithm should be one of the following:
232 .Bl -tag -width ".Ic sha256"
234 No checksum will be calculated for the data being send over the network.
235 This is the default setting.
237 CRC32 checksum will be calculated.
239 SHA256 checksum will be calculated.
241 .It Ic compression Aq algorithm
243 Compression algorithm should be one of the following:
244 .Bl -tag -width ".Ic none"
246 Data send over the network will not be compressed.
248 Only blocks that contain all zeros will be compressed.
249 This is very useful for initial synchronization where potentially many blocks
251 There should be no measurable performance overhead when this algorithm is being
253 This is the default setting.
255 The LZF algorithm by Marc Alexander Lehmann will be used to compress the data
256 send over the network.
257 LZF is very fast, general purpose compression algorithm.
259 .It Ic timeout Aq seconds
261 Connection timeout in seconds.
266 Execute the given program on various HAST events.
267 Below is the list of currently implemented events and arguments the given
268 program is executed with:
269 .Bl -tag -width ".Ic xxxx"
270 .It Ic "<path> role <resource> <oldrole> <newrole>"
272 Executed on both primary and secondary nodes when resource role is changed.
274 .It Ic "<path> connect <resource>"
276 Executed on both primary and secondary nodes when connection for the given
277 resource between the nodes is established.
279 .It Ic "<path> disconnect <resource>"
281 Executed on both primary and secondary nodes when connection for the given
282 resource between the nodes is lost.
284 .It Ic "<path> syncstart <resource>"
286 Executed on primary node when synchronization process of secondary node is
289 .It Ic "<path> syncdone <resource>"
291 Executed on primary node when synchronization process of secondary node is
292 completed successfully.
294 .It Ic "<path> syncintr <resource>"
296 Executed on primary node when synchronization process of secondary node is
297 interrupted, most likely due to secondary node outage or connection failure
300 .It Ic "<path> split-brain <resource>"
302 Executed on both primary and secondary nodes when split-brain condition is
308 argument should contain full path to executable program.
309 If the given program exits with code different than
312 will log it as an error.
316 argument is resource name from the configuration file.
320 argument is previous resource role (before the change).
328 argument is current resource role (after the change).
334 .It Ic metaflush on | off
338 flush write cache of the local provider after every metadata (activemap) update.
339 Flushing write cache ensures that provider will not reorder writes and that
340 metadata will be properly updated before real data is stored.
341 If the local provider does not support flushing write cache (it returns
355 GEOM provider name that will appear as
356 .Pa /dev/hast/<name> .
357 If name is not defined, resource name will be used as provider name.
360 Path to the local component which will be used as backend provider for
362 This can be either GEOM provider or regular file.
363 .It Ic remote Aq addr
365 Address of the remote
368 Format is the same as for the
371 When operating as a primary node this address will be used to connect to
373 When operating as a secondary node only connections from this address
378 can be used when the remote address is not yet known (eg. the other node is not
380 .It Ic source Aq addr
382 Local address to bind to before connecting to the remote
385 Format is the same as for the
390 .Bl -tag -width ".Pa /var/run/hastctl" -compact
391 .It Pa /etc/hast.conf
397 .It Pa /var/run/hastctl
398 Control socket used by the
400 control utility to communicate with the
405 The example configuration file can look as follows:
406 .Bd -literal -offset indent
410 listen tcp://2001:db8::1/64
413 listen tcp://2001:db8::2/64
420 remote tcp://10.0.0.2
423 remote tcp://10.0.0.1
428 local /dev/mirror/tanka
429 source tcp://10.0.0.1
430 remote tcp://10.0.0.2
433 local /dev/mirror/tankb
434 source tcp://10.0.0.2
435 remote tcp://10.0.0.1
448 .An Pawel Jakub Dawidek Aq pjd@FreeBSD.org
449 under sponsorship of the FreeBSD Foundation.