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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>
66 metaflush "on" | "off"
87 compression <algorithm>
92 metaflush "on" | "off"
95 # Resource-node section
99 metaflush "on" | "off"
105 # Resource-node section
109 metaflush "on" | "off"
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, or by node's UUID as found in the
137 The following statements are available:
138 .Bl -tag -width ".Ic xxxx"
139 .It Ic control Aq addr
141 Address for communication with
143 Each of the following examples defines the same control address:
144 .Bd -literal -offset indent
145 uds:///var/run/hastctl
146 unix:///var/run/hastctl
151 .Pa uds:///var/run/hastctl .
152 .It Ic pidfile Aq path
154 File in which to store the process ID of the main
159 .Pa /var/run/hastd.pid .
160 .It Ic listen Aq addr
162 Address to listen on in form of:
163 .Bd -literal -offset indent
164 protocol://protocol-specific-address
167 Each of the following examples defines the same listen address:
168 .Bd -literal -offset indent
177 Multiple listen addresses can be specified.
181 .Pa tcp4://0.0.0.0:8457
184 if kernel supports IPv4 and IPv6 respectively.
185 .It Ic replication Aq mode
187 Replication mode should be one of the following:
188 .Bl -tag -width ".Ic xxxx"
191 Report the write operation as completed when local write completes and
192 when the remote node acknowledges the data receipt, but before it
193 actually stores the data.
194 The data on remote node will be stored directly after sending
196 This mode is intended to reduce latency, but still provides a very good
198 The only situation where some small amount of data could be lost is when
199 the data is stored on primary node and sent to the secondary.
200 Secondary node then acknowledges data receipt and primary reports
201 success to an application.
202 However, it may happen that the secondary goes down before the received
203 data is really stored locally.
204 Before secondary node returns, primary node dies entirely.
205 When the secondary node comes back to life it becomes the new primary.
206 Unfortunately some small amount of data which was confirmed to be stored
207 to the application was lost.
208 The risk of such a situation is very small.
211 replication mode is currently not implemented.
214 Mark the write operation as completed when local as well as remote
216 This is the safest and the slowest replication mode.
219 replication mode is the default.
222 The write operation is reported as complete right after the local write
224 This is the fastest and the most dangerous replication mode.
225 This mode should be used when replicating to a distant node where
226 latency is too high for other modes.
228 .It Ic checksum Aq algorithm
230 Checksum algorithm should be one of the following:
231 .Bl -tag -width ".Ic sha256"
233 No checksum will be calculated for the data being send over the network.
234 This is the default setting.
236 CRC32 checksum will be calculated.
238 SHA256 checksum will be calculated.
240 .It Ic compression Aq algorithm
242 Compression algorithm should be one of the following:
243 .Bl -tag -width ".Ic none"
245 Data send over the network will not be compressed.
247 Only blocks that contain all zeros will be compressed.
248 This is very useful for initial synchronization where potentially many blocks
250 There should be no measurable performance overhead when this algorithm is being
252 This is the default setting.
254 The LZF algorithm by Marc Alexander Lehmann will be used to compress the data
255 send over the network.
256 LZF is very fast, general purpose compression algorithm.
258 .It Ic timeout Aq seconds
260 Connection timeout in seconds.
265 Execute the given program on various HAST events.
266 Below is the list of currently implemented events and arguments the given
267 program is executed with:
268 .Bl -tag -width ".Ic xxxx"
269 .It Ic "<path> role <resource> <oldrole> <newrole>"
271 Executed on both primary and secondary nodes when resource role is changed.
273 .It Ic "<path> connect <resource>"
275 Executed on both primary and secondary nodes when connection for the given
276 resource between the nodes is established.
278 .It Ic "<path> disconnect <resource>"
280 Executed on both primary and secondary nodes when connection for the given
281 resource between the nodes is lost.
283 .It Ic "<path> syncstart <resource>"
285 Executed on primary node when synchronization process of secondary node is
288 .It Ic "<path> syncdone <resource>"
290 Executed on primary node when synchronization process of secondary node is
291 completed successfully.
293 .It Ic "<path> syncintr <resource>"
295 Executed on primary node when synchronization process of secondary node is
296 interrupted, most likely due to secondary node outage or connection failure
299 .It Ic "<path> split-brain <resource>"
301 Executed on both primary and secondary nodes when split-brain condition is
307 argument should contain full path to executable program.
308 If the given program exits with code different than
311 will log it as an error.
315 argument is resource name from the configuration file.
319 argument is previous resource role (before the change).
327 argument is current resource role (after the change).
333 .It Ic metaflush on | off
337 flush write cache of the local provider after every metadata (activemap) update.
338 Flushing write cache ensures that provider will not reorder writes and that
339 metadata will be properly updated before real data is stored.
340 If the local provider does not support flushing write cache (it returns
354 GEOM provider name that will appear as
355 .Pa /dev/hast/<name> .
356 If name is not defined, resource name will be used as provider name.
359 Path to the local component which will be used as backend provider for
361 This can be either GEOM provider or regular file.
362 .It Ic remote Aq addr
364 Address of the remote
367 Format is the same as for the
370 When operating as a primary node this address will be used to connect to
372 When operating as a secondary node only connections from this address
377 can be used when the remote address is not yet known (eg. the other node is not
379 .It Ic source Aq addr
381 Local address to bind to before connecting to the remote
384 Format is the same as for the
389 .Bl -tag -width ".Pa /var/run/hastctl" -compact
390 .It Pa /etc/hast.conf
396 .It Pa /var/run/hastctl
397 Control socket used by the
399 control utility to communicate with the
404 The example configuration file can look as follows:
405 .Bd -literal -offset indent
409 listen tcp://2001:db8::1/64
412 listen tcp://2001:db8::2/64
419 remote tcp://10.0.0.2
422 remote tcp://10.0.0.1
427 local /dev/mirror/tanka
428 source tcp://10.0.0.1
429 remote tcp://10.0.0.2
432 local /dev/mirror/tankb
433 source tcp://10.0.0.2
434 remote tcp://10.0.0.1
447 .An Pawel Jakub Dawidek Aq pjd@FreeBSD.org
448 under sponsorship of the FreeBSD Foundation.