1LVM.CONF(5) File Formats Manual LVM.CONF(5)
2
6 lvm.conf - Configuration file for LVM2
7
9 /etc/lvm/lvm.conf
10
12 lvm.conf is loaded during the initialisation phase of lvm (8). This
13 file can in turn lead to other files being loaded - settings read in
14 later override earlier settings. File timestamps are checked between
15 commands and if any have changed, all the files are reloaded.
16 Use lvm dumpconfig to check what settings are in use.
18
20 This section describes the configuration file syntax.
21 Whitespace is not significant unless it is within quotes. This pro‐
23 vides a wide choice of acceptable indentation styles. Comments begin
24 with # and continue to the end of the line. They are treated as white‐
25 space.
26 Here is an informal grammar:
28 file = value*
30 A configuration file consists of a set of values.
31 value = section | assignment
33 A value can either be a new section, or an assignment.
34 section = identifier '{' value* '}'
36 A section is groups associated values together.
37 It is denoted by a name and delimited by curly brackets.
38 e.g. backup {
39 ...
40 }
41 assignment = identifier '=' (array | type)
43 An assignment associates a type with an identifier.
44 e.g. max_archives = 42
45 array = '[' (type ',')* type ']' | '[' ']'
47 Inhomogeneous arrays are supported.
48 Elements must be separated by commas.
49 An empty array is acceptable.
50 type = integer | float | string
52 integer = [0-9]*
53 float = [0-9]*.[0-9]*
54 string = '"' .* '"'
55 Strings must be enclosed in double quotes.
57
60 The sections that may be present in the file are:
61 devices — Device settings
63 dir — Directory in which to create volume group device nodes.
65 Defaults to "/dev". Commands also accept this as a prefix on
66 volume group names.
67 scan — List of directories to scan recursively for LVM physical
69 volumes. Devices in directories outside this hierarchy will be
70 ignored. Defaults to "/dev".
71 preferred_names — List of patterns compared in turn against all
73 the pathnames referencing the same device in in the scanned
74 directories. The pathname that matches the earliest pattern in
75 the list is the one used in any output. As an example, if
76 device-mapper multipathing is used, the following will select
77 multipath device names:
78 devices { preferred_names = [ "^/dev/mapper/mpath" ] }
79 filter — List of patterns to apply to devices found by a scan.
81 Patterns are regular expressions delimited by any character and
82 preceded by a (for accept) or r (for reject). The list is tra‐
83 versed in order, and the first regex that matches determines if
84 the device will be accepted or rejected (ignored). Devices that
85 don't match any patterns are accepted. If you want to reject
86 patterns that don't match, end the list with "r/.*/". If there
87 are several names for the same device (e.g. symbolic links in
88 /dev), if any name matches any a pattern, the device is
89 accepted; otherwise if any name matches any r pattern it is
90 rejected; otherwise it is accepted. As an example, to ignore
91 /dev/cdrom you could use:
92 devices { filter=["r|cdrom|"] }
93 cache_dir — Persistent filter cache file directory. Defaults to
95 "/etc/lvm/cache".
96 write_cache_state — Set to 0 to disable the writing out of the
98 persistent filter cache file when lvm exits. Defaults to 1.
99 types — List of pairs of additional acceptable block device
101 types found in /proc/devices together with maximum (non-zero)
102 number of partitions (normally 16). By default, LVM2 supports
103 ide, sd, md, loop, dasd, dac960, nbd, ida, cciss, ubd, ataraid,
104 drbd, power2, i2o_block and iseries/vd. Block devices with
105 major numbers of different types are ignored by LVM2. Example:
106 types = ["fd", 16]. To create physical volumes on device-mapper
107 volumes created outside LVM2, perhaps encrypted ones from crypt‐
108 setup, you'll need types = ["device-mapper", 16]. But if you do
109 this, be careful to avoid recursion within LVM2. The figure for
110 number of partitions is not currently used in LVM2 - and might
111 never be.
112 sysfs_scan — If set to 1 and your kernel supports sysfs and it
114 is mounted, sysfs will be used as a quick way of filtering out
115 block devices that are not present.
116 md_component_detection — If set to 1, LVM2 will ignore devices
118 used as components of software RAID (md) devices by looking for
119 md superblocks. This doesn't always work satisfactorily e.g. if
120 a device has been reused without wiping the md superblocks
121 first.
122 md_chunk_alignment — If set to 1, and a Physical Volume is
124 placed directly upon an md device, LVM2 will align its data
125 blocks with the md device's stripe-width.
126 data_alignment_detection — If set to 1, and your kernel provides
128 topology information in sysfs for the Physical Volume, the start
129 of data area will be aligned on a multiple of the ’mini‐
130 mum_io_size’ or ’optimal_io_size’ exposed in sysfs. mini‐
131 mum_io_size is the smallest request the device can perform with‐
132 out incurring a read-modify-write penalty (e.g. MD's chunk
133 size). optimal_io_size is the device's preferred unit of
134 receiving I/O (e.g. MD's stripe width). minimum_io_size is used
135 if optimal_io_size is undefined (0). If both md_chunk_alignment
136 and data_alignment_detection are enabled the result of
137 data_alignment_detection is used.
138 data_alignment — Default alignment (in KB) of start of data area
140 when creating a new Physical Volume using the lvm2 format. If a
141 Physical Volume is placed directly upon an md device and
142 md_chunk_alignment or data_alignment_detection is enabled this
143 parameter is ignored. Set to 0 to use the default alignment of
144 64KB or the page size, if larger.
145 data_alignment_offset_detection — If set to 1, and your kernel
147 provides topology information in sysfs for the Physical Volume,
148 the start of the aligned data area of the Physical Volume will
149 be shifted by the alignment_offset exposed in sysfs.
150 To see the location of the first Physical Extent of an existing
152 Physical Volume use pvs -o +pe_start . It will be a multiple of
153 the requested data_alignment plus the alignment_offset from
154 data_alignment_offset_detection (if enabled) or the pvcreate
155 commandline.
156 disable_after_error_count — During each LVM operation errors
158 received from each device are counted. If the counter of a par‐
159 ticular device exceeds the limit set here, no further I/O is
160 sent to that device for the remainder of the respective opera‐
161 tion. Setting the parameter to 0 disables the counters alto‐
162 gether.
163 allocation — Space allocation policies
165 cling_tag_list — List of PV tags matched by the cling allocation
167 policy.
168 When searching for free space to extend an LV, the cling alloca‐
170 tion policy will choose space on the same PVs as the last seg‐
171 ment of the existing LV. If there is insufficient space and a
172 list of tags is defined here, it will check whether any of them
173 are attached to the PVs concerned and then seek to match those
174 PV tags between existing extents and new extents.
175 The @ prefix for tags is required. Use the special tag "@*" as
177 a wildcard to match any PV tag and so use all PV tags for this
178 purpose.
179 For example, LVs are mirrored between two sites within a single
181 VG. PVs are tagged with either @site1 or @site2 to indicate
182 where they are situated and these two PV tags are selected for
183 use with this allocation policy:
184 cling_tag_list = [ "@site1", "@site2" ]
186 log — Default log settings
188 file — Location of log file. If this entry is not present, no
190 log file is written.
191 overwrite — Set to 1 to overwrite the log file each time a tool
193 is invoked. By default tools append messages to the log file.
194 level — Log level (0-9) of messages to write to the file. 9 is
196 the most verbose; 0 should produce no output.
197 verbose — Default level (0-3) of messages sent to stdout or
199 stderr. 3 is the most verbose; 0 should produce the least out‐
200 put.
201 syslog — Set to 1 (the default) to send log messages through
203 syslog. Turn off by setting to 0. If you set to an integer
204 greater than one, this is used - unvalidated - as the facility.
205 The default is LOG_USER. See /usr/include/sys/syslog.h for safe
206 facility values to use. For example, LOG_LOCAL0 might be 128.
207 indent — When set to 1 (the default) messages are indented
209 according to their severity, two spaces per level. Set to 0 to
210 turn off indentation.
211 command_names — When set to 1, the command name is used as a
213 prefix for each message. Default is 0 (off).
214 prefix — Prefix used for all messages (after the command name).
216 Default is two spaces.
217 activation — Set to 1 to log messages while devices are sus‐
219 pended during activation. Only set this temporarily while
220 debugging a problem because in low memory situations this set‐
221 ting can cause your machine to lock up.
222 backup — Configuration for metadata backups.
224 archive_dir — Directory used for automatic metadata archives.
226 Backup copies of former metadata for each volume group are
227 archived here. Defaults to "/etc/lvm/archive".
228 backup_dir — Directory used for automatic metadata backups. A
230 single backup copy of the current metadata for each volume group
231 is stored here. Defaults to "/etc/lvm/backup".
232 archive — Whether or not tools automatically archive existing
234 metadata into archive_dir before making changes to it. Default
235 is 1 (automatic archives enabled). Set to 0 to disable. Dis‐
236 abling this might make metadata recovery difficult or impossible
237 if something goes wrong.
238 backup — Whether or not tools make an automatic backup into
240 backup_dir after changing metadata. Default is 1 (automatic
241 backups enabled). Set to 0 to disable. Disabling this might
242 make metadata recovery difficult or impossible if something goes
243 wrong.
244 retain_min — Minimum number of archives to keep. Defaults to
246 10.
247 retain_days — Minimum number of days to keep archive files.
249 Defaults to 30.
250 shell — LVM2 built-in readline shell settings
252 history_size — Maximum number of lines of shell history to
254 retain (default 100) in $HOME/.lvm_history
255 global — Global settings
257 test — If set to 1, run tools in test mode i.e. no changes to
259 the on-disk metadata will get made. It's equivalent to having
260 the -t option on every command.
261 activation — Set to 0 to turn off all communication with the
263 device-mapper driver. Useful if you want to manipulate logical
264 volumes while device-mapper is not present in your kernel.
265 proc — Mount point of proc filesystem. Defaults to /proc.
267 umask — File creation mask for any files and directories cre‐
269 ated. Interpreted as octal if the first digit is zero.
270 Defaults to 077. Use 022 to allow other users to read the files
271 by default.
272 format — The default value of --metadatatype used to determine
274 which format of metadata to use when creating new physical vol‐
275 umes and volume groups. lvm1 or lvm2.
276 fallback_to_lvm1 — Set this to 1 if you need to be able to
278 switch between 2.4 kernels using LVM1 and kernels including
279 device-mapper. The LVM2 tools should be installed as normal and
280 the LVM1 tools should be installed with a .lvm1 suffix e.g.
281 vgscan.lvm1. If an LVM2 tool is then run but unable to communi‐
282 cate with device-mapper, it will automatically invoke the equiv‐
283 alent LVM1 version of the tool. Note that for LVM1 tools to
284 manipulate physical volumes and volume groups created by LVM2
285 you must use --metadataformat lvm1 when creating them.
286 library_dir — A directory searched for LVM2's shared libraries
288 ahead of the places dlopen (3) searches.
289 format_libraries — A list of shared libraries to load that con‐
291 tain code to process different formats of metadata. For example,
292 liblvm2formatpool.so is needed to read GFS pool metadata if LVM2
293 was configured --with-pool=shared.
294 locking_type — What type of locking to use. 1 is the default,
296 which use flocks on files in locking_dir (see below) to avoid
297 conflicting LVM2 commands running concurrently on a single
298 machine. 0 disables locking and risks corrupting your metadata.
299 If set to 2, the tools will load the external locking_library
300 (see below). If the tools were configured --with-cluster=inter‐
301 nal (the default) then 3 means to use built-in cluster-wide
302 locking. Type 4 enforces read-only metadata and forbids any
303 operations that might want to modify Volume Group metadata. All
304 changes to logical volumes and their states are communicated
305 using locks.
306 wait_for_locks — When set to 1, the default, the tools wait if a
308 lock request cannot be satisfied immediately. When set to 0,
309 the operation is aborted instead.
310 locking_dir — The directory LVM2 places its file locks if lock‐
312 ing_type is set to 1. The default is /var/lock/lvm.
313 locking_library — The name of the external locking library to
315 load if locking_type is set to 2. The default is liblvm2clus‐
316 terlock.so. If you need to write such a library, look at the
317 lib/locking source code directory.
318 tags — Host tag settings
320 hosttags — If set to 1, create a host tag with the machine name.
322 Setting this to 0 does nothing, neither creating nor destroying
323 any tag. The machine name used is the nodename as returned by
324 uname (2).
325 Additional host tags to be set can be listed here as subsec‐
327 tions. The @ prefix for tags is optional. Each of these host
328 tag subsections can contain a host_list array of host names. If
329 any one of these entries matches the machine name exactly then
330 the host tag gets defined on this particular host, otherwise it
331 doesn't.
332 After lvm.conf has been processed, LVM2 works through each host
334 tag that has been defined in turn, and if there is a configura‐
335 tion file called lvm_<host_tag>.conf it attempts to load it.
336 Any settings read in override settings found in earlier files.
337 Any additional host tags defined get appended to the search
338 list, so in turn they can lead to further configuration files
339 being processed. Use lvm dumpconfig to check the result of con‐
340 fig file processing.
341 The following example always sets host tags tag1 and sets tag2
343 on machines fs1 and fs2:
344 tags { tag1 { } tag2 { host_list = [ "fs1", "fs2" ] } }
346 These options are useful if you are replicating configuration
348 files around a cluster. Use of hosttags = 1 means every machine
349 can have static and identical local configuration files yet use
350 different settings and activate different logical volumes by
351 default. See also volume_list below and --addtag in lvm (8).
352 activation — Settings affecting device-mapper activation
354 missing_stripe_filler — When activating an incomplete logical
356 volume in partial mode, this option dictates how the missing
357 data is replaced. A value of "error" will cause activation to
358 create error mappings for the missing data, meaning that read
359 access to missing portions of the volume will result in I/O
360 errors. You can instead also use a device path, and in that case
361 this device will be used in place of missing stripes. However,
362 note that using anything other than "error" with mirrored or
363 snapshotted volumes is likely to result in data corruption. For
364 instructions on how to create a device that always returns
365 zeros, see lvcreate (8).
366 mirror_region_size — Unit size in KB for copy operations when
368 mirroring.
369 readahead — Used when there is no readahead value stored in the
371 volume group metadata. Set to none to disable readahead in
372 these circumstances or auto to use the default value chosen by
373 the kernel.
374 reserved_memory, reserved_stack — How many KB to reserve for
376 LVM2 to use while logical volumes are suspended. If insuffi‐
377 cient memory is reserved before suspension, there is a risk of
378 machine deadlock.
379 process_priority — The nice value to use while devices are sus‐
381 pended. This is set to a high priority so that logical volumes
382 are suspended (with I/O generated by other processes to those
383 logical volumes getting queued) for the shortest possible time.
384 volume_list — This acts as a filter through which all requests
386 to activate a logical volume on this machine are passed. A log‐
387 ical volume is only activated if it matches an item in the list.
388 Tags must be preceded by @ and are checked against all tags
389 defined in the logical volume and volume group metadata for a
390 match. @* is short-hand to check every tag set on the host
391 machine (see tags above). Logical volume and volume groups can
392 also be included in the list by name e.g. vg00, vg00/lvol1.
393 metadata — Advanced metadata settings
395 pvmetadatacopies — When creating a physical volume using the
397 LVM2 metadata format, this is the default number of copies of
398 metadata to store on each physical volume. Currently it can be
399 set to 0, 1 or 2. The default is 1. If set to 2, one copy is
400 placed at the beginning of the disk and the other is placed at
401 the end. It can be overridden on the command line with
402 --pvmetadatacopies (see pvcreate). If creating a volume group
403 with just one physical volume, it's a good idea to have 2
404 copies. If creating a large volume group with many physical
405 volumes, you may decide that 3 copies of the metadata is suffi‐
406 cient, i.e. setting it to 1 on three of the physical volumes,
407 and 0 on the rest. Every volume group must contain at least one
408 physical volume with at least 1 copy of the metadata (unless
409 using the text files described below). The disadvantage of hav‐
410 ing lots of copies is that every time the tools access the vol‐
411 ume group, every copy of the metadata has to be accessed, and
412 this slows down the tools.
413 pvmetadatasize — Approximate number of sectors to set aside for
415 each copy of the metadata. Volume groups with large numbers of
416 physical or logical volumes, or volumes groups containing com‐
417 plex logical volume structures will need additional space for
418 their metadata. The metadata areas are treated as circular buf‐
419 fers, so unused space becomes filled with an archive of the most
420 recent previous versions of the metadata.
421 pvmetadataignore When creating a physical volume using the LVM2
423 metadata format, this states whether metadata areas should be
424 ignored. The default is "n". If metadata areas on a physical
425 volume are ignored, LVM will not not store metadata in the meta‐
426 data areas present on newly created Physical Volumes. The
427 option can be overridden on the command line with --metadataig‐
428 nore (See pvcreate and pvchange). Metadata areas cannot be cre‐
429 ated or extended after Logical Volumes have been allocated on
430 the device. If you do not want to store metadata on this
431 device, it is still wise always to allocate a metadata area (use
432 a non-zero value for --pvmetadatacopies) in case you need it in
433 the future and to use this option to instruct LVM2 to ignore it.
434 vgmetadatacopies — When creating a volume group using the LVM2
436 metadata format, this is the default number of copies of meta‐
437 data desired across all the physical volumes in the volume
438 group. If set to a non-zero value, LVM will automatically set
439 or clear the metadataignore flag on the physical volumes (see
440 pvcreate and pvchange --metadataignore) in order to achieve the
441 desired number of metadata copies. An LVM command that adds or
442 removes physical volumes (for example, vgextend, vgreduce,
443 vgsplit, or vgmerge), may cause LVM to automatically set or
444 clear the metadataignore flags. Also, if physical volumes go
445 missing or reappear, or a new number of copies is explicitly set
446 (see vgchange --vgmetadatacopies), LVM may adjust the meta‐
447 dataignore flags. Set vgmetadatacopies to 0 instructs LVM not
448 to set or clear the metadataignore flags automatically. You may
449 set a value larger than the sum of all metadata areas on all
450 physical volumes. The value can be overridden on the command
451 line with --vgmetadatacopies for various commands (for example,
452 vgcreate and vgchange), and can be queryied with the
453 vg_mda_copies field of vgs. This option is useful for volume
454 groups containing large numbers of physical volumes with meta‐
455 data as it may be used to minimize metadata read and write over‐
456 head.
457 dirs — List of directories holding live copies of LVM2 metadata
459 as text files. These directories must not be on logical vol‐
460 umes. It is possible to use LVM2 with a couple of directories
461 here, preferably on different (non-logical-volume) filesystems
462 and with no other on-disk metadata, pvmetadatacopies = 0.
463 Alternatively these directories can be in addition to the on-
464 disk metadata areas. This feature was created during the devel‐
465 opment of the LVM2 metadata before the new on-disk metadata
466 areas were designed and no longer gets tested. It is not sup‐
467 ported under low-memory conditions, and it is important never to
468 edit these metadata files unless you fully understand how things
469 work: to make changes you should always use the tools as normal,
470 or else vgcfgbackup, edit backup, vgcfgrestore.
471
473 /etc/lvm/lvm.conf /etc/lvm/archive /etc/lvm/backup
474 /etc/lvm/cache/.cache /var/lock/lvm
475
477 lvm(8), umask(2), uname(2), dlopen(3), syslog(3), syslog.conf(5)
478Sistina Software UK LVM TOOLS 2.02.84(2) (2011-02-09) LVM.CONF(5)