tfossil.4 - plan9port - [fork] Plan 9 from user space
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---
tfossil.4 (10027B)
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1 .TH FOSSIL 4
2 .SH NAME
3 fossil, flchk, flfmt \- archival file server
4 .SH SYNOPSIS
5 .B fossil/fossil
6 [
7 .B -Dt
8 ]
9 [
10 .B -c
11 .I cmd
12 ]...
13 [
14 .B -f
15 .I file
16 ]
17 [
18 .B -m
19 .I free-memory-percent
20 ]
21 .PP
22 .B fossil/flchk
23 [
24 .B -f
25 ]
26 [
27 .B -c
28 .I ncache
29 ]
30 [
31 .B -h
32 .I host
33 ]
34 .I file
35 .PP
36 .B fossil/flfmt
37 [
38 .B -y
39 ]
40 [
41 .B -b
42 .I blocksize
43 ]
44 [
45 .B -h
46 .I host
47 ]
48 [
49 .B -l
50 .I label
51 ]
52 [
53 .B -v
54 .I score
55 ]
56 .I file
57 .PP
58 .B fossil/conf
59 [
60 .B -w
61 ]
62 .I file
63 [
64 .I config
65 ]
66 .PP
67 .B fossil/last
68 .I file
69 .SH DESCRIPTION
70 .I Fossil
71 is the main file system for Plan 9.
72 Unlike the Plan 9 file servers of old,
73 .I fossil
74 is a collection of user-space programs that run on a standard Plan 9 kernel.
75 The name of the main fossil file server at Murray Hill is
76 .BR pie .
77 The Plan 9 distribution file server,
78 .BR sources ,
79 is also a fossil server.
80 .PP
81 .I Fossil
82 is structured as a magnetic disk write buffer
83 optionally backed by a Venti server for archival storage.
84 It serves the Plan 9 protocol via TCP.
85 A
86 .I fossil
87 file server conventionally presents
88 three trees in the root directory of each file system:
89 .BR active ,
90 .BR archive ,
91 and
92 .BR snapshot .
93 .B /active
94 is the root of a conventional file system
95 whose blocks are stored in a disk file.
96 In a typical configuration, the file server periodically
97 marks the entire file system copy-on-write, effectively
98 taking a snapshot of the file system at that moment.
99 This snapshot is made available in a name
100 created from the date and time of the snapshot:
101 .BI /snapshot/ yyyy / mmdd / hhmm \fR,
102 where
103 .I yyyy
104 is the full year,
105 .I mm
106 is the month number,
107 .I dd
108 is the day number,
109 .I hh
110 is the hour,
111 and
112 .I mm
113 is the minute.
114 The snapshots in
115 .B /snapshot
116 are ephemeral: eventually they are deleted
117 to reclaim the disk space they occupy.
118 Long-lasting snapshots stored on a Venti server
119 are kept in
120 .B /archive
121 and also named from the date (though not the time) of the snapshot:
122 .BI /archive/ yyyy / mmdds \fR,
123 where
124 .IR yyyy ,
125 .IR mm ,
126 and
127 .I dd
128 are year, month, and day as before,
129 and
130 .I s
131 is a sequence number if more than one
132 archival snapshot is done in a day.
133 For the first snapshot,
134 .I s
135 is null.
136 For the subsequent snapshots,
137 .I s
138 is
139 .BR .1 ,
140 .BR .2 ,
141 .BR .3 ,
142 etc.
143 The root of the main file system that is frozen
144 for the first archival snapshot of December 15, 2002
145 will be named
146 .BR /archive/2002/1215/ .
147 .PP
148 The attach name used in
149 .I mount
150 (see
151 .MR bind (1) ,
152 .MR bind (2)
153 and
154 .MR attach (5) )
155 selects a file system to be served
156 and optionally a subtree,
157 in the format
158 .IB fs \fR[\fB/ dir \fR].
159 An empty attach name selects
160 .BR main/active .
161 .PP
162 .I Fossil
163 normally requires all users except
164 .L none
165 to provide authentication tickets on each
166 .MR attach (5) .
167 To keep just anyone from connecting,
168 .L none
169 is only allowed to attach after another user
170 has successfully attached on the same
171 connection.
172 The other user effectively acts as a chaperone
173 for
174 .LR none .
175 Authentication can be disabled using the
176 .B -A
177 flag to
178 .B open
179 or
180 .B srv
181 (see
182 .MR fossilcons (8) ).
183 .PP
184 The groups called
185 .B noworld
186 and
187 .B write
188 are special on the file server.
189 Any user belonging to
190 .B noworld
191 has attenuated access privileges.
192 Specifically, when checking such a user's access to files,
193 the file's permission bits are first ANDed
194 with 0770 for normal files and 0771 for directories.
195 The effect is to deny world access permissions to
196 .B noworld
197 users, except when walking into directories.
198 If the
199 .B write
200 group exists, then the file system appears read-only
201 to users not in the group.
202 This is used to make the Plan 9 distribution file server
203 .RI ( sources.cs.bell-labs.com )
204 readable by the world but writable only to the developers.
205 .PP
206 .I Fossil
207 starts a new instance of the fossil file server.
208 It is configured mainly through console commands,
209 documented in
210 .MR fossilcons (8) .
211 .PP
212 The options are:
213 .TF "-c\fI cmd
214 .PD
215 .TP
216 .B -D
217 Toggle the debugging flag, which is initially off.
218 When the flag is set, information about authentication
219 and all protocol messages are written to standard error.
220 .TP
221 .B -t
222 Start a file server console on
223 .BR /dev/cons .
224 If this option is given,
225 .I fossil
226 does not fork itself into the background.
227 .TP
228 .BI -c " cmd
229 Execute the console command
230 .IR cmd .
231 This option may be repeated to give multiple
232 commands.
233 Typically the only commands given on the
234 command line are
235 .RB `` ".\fI file" ,''
236 which executes a file containing commands,
237 and
238 .RB `` "srv -p" \fIcons \fR,''
239 which starts a file server console on
240 .BI /srv/ cons \fR.
241 See
242 .MR fossilcons (8)
243 for more information.
244 .TP
245 .BI -f " file
246 Read and execute console commands stored in the Fossil disk
247 .IR file .
248 .I Conf
249 .RI ( q.v. )
250 reads and writes the command set stored in the disk.
251 .TP
252 .B -m
253 Allocate
254 .I free-memory-percent
255 percent of the available free RAM for buffers.
256 This overrides all other memory sizing parameters,
257 notably the
258 .B -c
259 option to
260 .BR open .
261 30% is a reasonable choice.
262 .PD
263 .PP
264 .I Flchk
265 checks the fossil file system stored in
266 .I file
267 for inconsistencies.
268 .I Flchk
269 is deprecated in favor of the console
270 .B check
271 command (see
272 .MR fossilcons (8) ).
273 .I Flchk
274 prints
275 .I fossil
276 console commands that may be
277 executed to take care of
278 bad pointers
279 .RB ( clrp ),
280 bad entries
281 .RB ( clre ),
282 bad directory entries
283 .RB ( clri ),
284 unreachable blocks
285 .RB ( bfree ).
286 Console commands are interspersed with
287 more detailed commentary on the file system.
288 The commands are distinguished by being prefixed with
289 sharp signs.
290 Note that all proposed fixes are rather drastic: offending
291 pieces of file system are simply chopped off.
292 .PP
293 .I Flchk
294 does
295 .I not
296 modify the file system, so it is safe to
297 run concurrently with
298 .IR fossil ,
299 though in this case
300 the list of unreachable
301 blocks and any inconsistencies involving the active file system
302 should be taken with a grain of salt.
303 .PP
304 The options are:
305 .TF "-h\fI host
306 .PD
307 .TP
308 .B -f
309 Fast mode.
310 By default,
311 .I flchk
312 checks the entire file system image for consistency,
313 which includes all the archives to Venti
314 and can take a very long time.
315 In fast mode,
316 .I flchk
317 avoids walking in Venti blocks
318 whenever possible.
319 .TP
320 .BI -c " ncache
321 Keep a cache of
322 .I ncache
323 (by default, 1000)
324 file system blocks in memory during the check.
325 .TP
326 .BI -h " host
327 Use
328 .I host
329 as the Venti server.
330 .PD
331 .PP
332 .I Flfmt
333 prepares
334 .I file
335 as a new fossil file system.
336 The file system is initialized with three empty directories
337 .BR active ,
338 .BR archive ,
339 and
340 .BR snapshot ,
341 as described above.
342 The options are:
343 .TF "-b\fI blocksize
344 .PD
345 .TP
346 .B -y
347 Yes mode.
348 By default,
349 .I flfmt
350 will prompt for confirmation before formatting
351 a file that already contains a fossil file system,
352 and before formatting a file that is not served
353 directly by a kernel device.
354 If the
355 .B -y
356 flag is given, no such checks are made.
357 .TP
358 .BI -b " blocksize
359 Set the file system block size (by default, 8192).
360 .TP
361 .BI -h " host
362 Use
363 .I host
364 as the Venti server.
365 .TP
366 .BI -l " label
367 Set the textual label on the file system to
368 .IR label .
369 The label is only a comment.
370 .TP
371 .BI -v " score
372 Initialize the file system using the vac file
373 system stored on Venti at
374 .IR score .
375 The score should have been generated by
376 .I fossil
377 rather than by
378 .MR vac (1) ,
379 so that the appropriate snapshot metadata is present.
380 .PD
381 .PP
382 .I Conf
383 reads or writes the configuration branded on the Fossil disk
384 .IR file .
385 By default, it reads the configuration from the disk and prints it to
386 standard output.
387 If the
388 .B -w
389 flag is given,
390 .I conf
391 reads a new configuration from
392 .I config
393 (or else from standard input)
394 and writes it to the disk.
395 Inside the configuration file, the argument
396 .L *
397 may be used to stand in for the name of the disk holding the configuration.
398 The Plan 9 kernel boot process runs
399 .RB `` fossil
400 .B -f
401 .IR disk ''
402 to start a Fossil file server.
403 The disk is just a convenient place to store configuration
404 information.
405 .PP
406 .I Last
407 prints the vac score that resulted after the most recent archival snapshot
408 of the fossil in
409 .I file.
410 .SH EXAMPLES
411 .PP
412 Place the root of the archive file system on
413 .B /n/dump
414 and show the modified times of the MIPS C compiler
415 over all dumps in December 2002:
416 .IP
417 .EX
418 9fs dump
419 ls -l /n/dump/2002/12*/mips/bin/vc
420 .EE
421 .PP
422 To get only one line of output for each version of the compiler:
423 .IP
424 .EX
425 ls -lp /n/dump/2002/12*/mips/bin/vc | uniq
426 .EE
427 .ne 14
428 .PP
429 Initialize a new file system, start the server with permission
430 checking turned off, create a users file, and mount the server:
431 .IP
432 .EX
433 fossil/flfmt /dev/sdC0/fossil
434 fossil/conf -w /dev/sdC0/fossil <<EOF
435 fsys main config
436 fsys main open -AWP
437 fsys main
438 create /active/adm adm sys d775
439 create /active/adm/users adm sys 664
440 users -w
441 srv -p fscons
442 srv fossil
443 EOF
444 fossil/fossil -f /dev/sdC0/fossil
445 mount /srv/fossil /n/fossil
446 .EE
447 .LP
448 See the discussion of the
449 .B users
450 and
451 .B uname
452 commands in
453 .MR fossilcons (8)
454 for more about the user table.
455 .ne 3
456 .PP
457 Perhaps because the disk has been corrupted or replaced,
458 format a new file system using the last archive score printed
459 on the console:
460 .IP
461 .EX
462 fossil/flfmt -v b9b3...5559 /dev/sdC0/fossil
463 .EE
464 .LP
465 Note that while
466 .B /snapshot
467 will be lost,
468 .B /active
469 and
470 .B /archive
471 will be restored to their contents at the time of the
472 last archival snapshot.
473 .ne 3
474 .PP
475 Blindly accept the changes prescribed by
476 .I flchk
477 (not recommended):
478 .IP
479 .EX
480 fossil/flchk /dev/sdC0/fossil | sed -n 's/^# //p' >>/srv/fscons
481 .EE
482 .LP
483 A better strategy is to vet the output,
484 filter out any suggestions you're not comfortable with,
485 and then use the
486 .I sed
487 command to prepare the script.
488 .SH SOURCE
489 .B \*9/src/cmd/fossil
490 .SH SEE ALSO
491 .MR yesterday (1) ,
492 .MR fs (3) ,
493 .MR fs (4) ,
494 .MR srv (4) ,
495 .MR fossilcons (8) ,
496 .MR loadfossil (8) ,
497 .MR venti (8)
498 .SH BUGS
499 It is possible that the disk format (but not the Venti format)
500 will change in the future, to make the disk a full cache
501 rather than just a write buffer.
502 Changing to the new format will require reformatting
503 the disk as in the example above,
504 but note that this will preserve most of the file system
505 (all but
506 .BR /snapshot )
507 with little effort.
508 .PP
509 The
510 .B -m
511 option currently assumes a block size of 8K bytes,
512 and a single file system per
513 .I fossil
514 instance.