1LVCONVERT(8) System Manager's Manual LVCONVERT(8)
2
6 lvconvert - Change logical volume layout
7
9 lvconvert option_args position_args
10 [ option_args ]
11 [ position_args ]
12 --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
14 -b|--background
15 -H|--cache
16 --cachemetadataformat auto|1|2
17 --cachemode writethrough|writeback|passthrough
18 --cachepolicy String
19 --cachepool LV
20 --cachesettings String
21 -c|--chunksize Size[k|UNIT]
22 --commandprofile String
23 --compression y|n
24 --config String
25 -d|--debug
26 --deduplication y|n
27 --discards passdown|nopassdown|ignore
28 --driverloaded y|n
29 -f|--force
30 -h|--help
31 -i|--interval Number
32 --lockopt String
33 --longhelp
34 --merge
35 --mergemirrors
36 --mergesnapshot
37 --mergethin
38 --metadataprofile String
39 --mirrorlog core|disk
40 -m|--mirrors [+|-]Number
41 -n|--name String
42 --nolocking
43 --noudevsync
44 --originname LV
45 --poolmetadata LV
46 --poolmetadatasize Size[m|UNIT]
47 --poolmetadataspare y|n
48 --profile String
49 -q|--quiet
50 -r|--readahead auto|none|Number
51 -R|--regionsize Size[m|UNIT]
52 --repair
53 --replace PV
54 -s|--snapshot
55 --splitcache
56 --splitmirrors Number
57 --splitsnapshot
58 --startpoll
59 --stripes Number
60 -I|--stripesize Size[k|UNIT]
61 --swapmetadata
62 -t|--test
63 -T|--thin
64 --thinpool LV
65 --trackchanges
66 --type linear|striped|snapshot|mir‐
67 ror|raid|thin|cache|thin-pool|cache-pool
68 --uncache
69 --usepolicies
70 --vdopool LV
71 -v|--verbose
72 --version
73 -V|--virtualsize Size[m|UNIT]
74 -y|--yes
75 -Z|--zero y|n
76
78 lvconvert changes the LV type and includes utilities for LV data main‐
79 tenance. The LV type controls data layout and redundancy. The LV type
80 is also called the segment type or segtype.
81 To display the current LV type, run the command:
83 lvs -o name,segtype LV
85 In some cases, an LV is a single device mapper (dm) layer above physi‐
87 cal devices. In other cases, hidden LVs (dm devices) are layered
88 between the visible LV and physical devices. LVs in the middle layers
89 are called sub LVs. A command run on a visible LV sometimes operates
90 on a sub LV rather than the specified LV. In other cases, a sub LV
91 must be specified directly on the command line.
92 Sub LVs can be displayed with the command:
94 lvs -a
96 The linear type is equivalent to the striped type when one stripe
98 exists. In that case, the types can sometimes be used interchangably.
99 In most cases, the mirror type is deprecated and the raid1 type should
101 be used. They are both implementations of mirroring.
102 Striped raid types are raid0/raid0_meta, raid5 (an alias for raid5_ls),
104 raid6 (an alias for raid6_zr) and raid10 (an alias for raid10_near).
105 As opposed to mirroring, raid5 and raid6 stripe data and calculate par‐
107 ity blocks. The parity blocks can be used for data block recovery in
108 case devices fail. A maximum number of one device in a raid5 LV may
109 fail, and two in case of raid6. Striped raid types typically rotate the
110 parity and data blocks for performance reasons, thus avoiding con‐
111 tention on a single device. Specific arrangements of parity and data
112 blocks (layouts) can be used to optimize I/O performance, or to convert
113 between raid levels. See lvmraid(7) for more information.
114 Layouts of raid5 rotating parity blocks can be: left-asymmetric
116 (raid5_la), left-symmetric (raid5_ls with alias raid5), right-asymmet‐
117 ric (raid5_ra), right-symmetric (raid5_rs) and raid5_n, which doesn't
118 rotate parity blocks. Layouts of raid6 are: zero-restart (raid6_zr with
119 alias raid6), next-restart (raid6_nr), and next-continue (raid6_nc).
120 Layouts including _n allow for conversion between raid levels (raid5_n
122 to raid6 or raid5_n to striped/raid0/raid0_meta). Additionally, special
123 raid6 layouts for raid level conversions between raid5 and raid6 are:
124 raid6_ls_6, raid6_rs_6, raid6_la_6 and raid6_ra_6. Those correspond to
125 their raid5 counterparts (e.g. raid5_rs can be directly converted to
126 raid6_rs_6 and vice-versa).
127 raid10 (an alias for raid10_near) is currently limited to one data copy
129 and even number of sub LVs. This is a mirror group layout, thus a sin‐
130 gle sub LV may fail per mirror group without data loss.
131 Striped raid types support converting the layout, their stripesize and
133 their number of stripes.
134 The striped raid types combined with raid1 allow for conversion from
136 linear-> striped/raid0/raid0_meta and vice-versa by e.g. linear <->
137 raid1 <-> raid5_n (then adding stripes) <-> striped/raid0/raid0_meta.
138
140 Convert LV to linear.
141 lvconvert --type linear LV
143 [ COMMON_OPTIONS ]
144 [ PV ... ]
145 -
146 Convert LV to striped.
148 lvconvert --type striped LV
150 [ -I|--stripesize Size[k|UNIT] ]
151 [ -R|--regionsize Size[m|UNIT] ]
152 [ -i|--interval Number ]
153 [ --stripes Number ]
154 [ COMMON_OPTIONS ]
155 [ PV ... ]
156 -
157 Convert LV to raid or change raid layout
159 (a specific raid level must be used, e.g. raid1).
160 lvconvert --type raid LV
162 [ -m|--mirrors [+|-]Number ]
163 [ -I|--stripesize Size[k|UNIT] ]
164 [ -R|--regionsize Size[m|UNIT] ]
165 [ -i|--interval Number ]
166 [ --stripes Number ]
167 [ COMMON_OPTIONS ]
168 [ PV ... ]
169 -
170 Convert LV to raid1 or mirror, or change number of mirror images.
172 lvconvert -m|--mirrors [+|-]Number LV
174 [ -R|--regionsize Size[m|UNIT] ]
175 [ -i|--interval Number ]
176 [ --mirrorlog core|disk ]
177 [ COMMON_OPTIONS ]
178 [ PV ... ]
179 -
180 Convert raid LV to change number of stripe images.
182 lvconvert --stripes Number LV_raid
184 [ -i|--interval Number ]
185 [ -R|--regionsize Size[m|UNIT] ]
186 [ -I|--stripesize Size[k|UNIT] ]
187 [ COMMON_OPTIONS ]
188 [ PV ... ]
189 -
190 Convert raid LV to change the stripe size.
192 lvconvert -I|--stripesize Size[k|UNIT] LV_raid
194 [ -i|--interval Number ]
195 [ -R|--regionsize Size[m|UNIT] ]
196 [ COMMON_OPTIONS ]
197 -
198 Split images from a raid1 or mirror LV and use them to create a new LV.
200 lvconvert --splitmirrors Number -n|--name LV_new LV_cache_mirror_raid1
202 [ COMMON_OPTIONS ]
203 [ PV ... ]
204 -
205 Split images from a raid1 LV and track changes to origin for later
207 merge.
208 lvconvert --splitmirrors Number --trackchanges LV_cache_raid1
210 [ COMMON_OPTIONS ]
211 [ PV ... ]
212 -
213 Merge LV images that were split from a raid1 LV.
215 lvconvert --mergemirrors VG|LV_linear_raid|Tag ...
217 [ COMMON_OPTIONS ]
218 -
219 Convert LV to a thin LV, using the original LV as an external origin.
221 lvconvert --type thin --thinpool LV LV_linear_striped_thin_cache_raid
223 [ -T|--thin ]
224 [ -r|--readahead auto|none|Number ]
225 [ -c|--chunksize Size[k|UNIT] ]
226 [ -Z|--zero y|n ]
227 [ --originname LV_new ]
228 [ --poolmetadata LV ]
229 [ --poolmetadatasize Size[m|UNIT] ]
230 [ --poolmetadataspare y|n ]
231 [ --metadataprofile String ]
232 [ COMMON_OPTIONS ]
233 -
234 Convert LV to type cache.
236 lvconvert --type cache --cachepool LV LV_linear_striped_thinpool_raid
238 [ -H|--cache ]
239 [ -Z|--zero y|n ]
240 [ -r|--readahead auto|none|Number ]
241 [ -c|--chunksize Size[k|UNIT] ]
242 [ --cachemetadataformat auto|1|2 ]
243 [ --cachemode writethrough|writeback|passthrough ]
244 [ --cachepolicy String ]
245 [ --cachesettings String ]
246 [ --poolmetadata LV ]
247 [ --poolmetadatasize Size[m|UNIT] ]
248 [ --poolmetadataspare y|n ]
249 [ --metadataprofile String ]
250 [ COMMON_OPTIONS ]
251 -
252 Convert LV to type thin-pool.
254 lvconvert --type thin-pool LV_linear_striped_cache_raid
256 [ -I|--stripesize Size[k|UNIT] ]
257 [ -r|--readahead auto|none|Number ]
258 [ -c|--chunksize Size[k|UNIT] ]
259 [ -Z|--zero y|n ]
260 [ --stripes Number ]
261 [ --discards passdown|nopassdown|ignore ]
262 [ --poolmetadata LV ]
263 [ --poolmetadatasize Size[m|UNIT] ]
264 [ --poolmetadataspare y|n ]
265 [ --metadataprofile String ]
266 [ COMMON_OPTIONS ]
267 [ PV ... ]
268 -
269 Convert LV to type cache-pool.
271 lvconvert --type cache-pool LV_linear_striped_raid
273 [ -Z|--zero y|n ]
274 [ -r|--readahead auto|none|Number ]
275 [ -c|--chunksize Size[k|UNIT] ]
276 [ --cachemetadataformat auto|1|2 ]
277 [ --cachemode writethrough|writeback|passthrough ]
278 [ --cachepolicy String ]
279 [ --cachesettings String ]
280 [ --poolmetadata LV ]
281 [ --poolmetadatasize Size[m|UNIT] ]
282 [ --poolmetadataspare y|n ]
283 [ --metadataprofile String ]
284 [ COMMON_OPTIONS ]
285 [ PV ... ]
286 -
287 Convert LV to type vdopool.
289 lvconvert --type vdo-pool LV_linear_striped_cache_raid
291 [ -n|--name LV_new ]
292 [ -V|--virtualsize Size[m|UNIT] ]
293 [ --compression y|n ]
294 [ --deduplication y|n ]
295 [ COMMON_OPTIONS ]
296 -
297 Separate and keep the cache pool from a cache LV.
299 lvconvert --splitcache LV_thinpool_cache_cachepool
301 [ COMMON_OPTIONS ]
302 -
303 Merge thin LV into its origin LV.
305 lvconvert --mergethin LV_thin ...
307 [ COMMON_OPTIONS ]
308 -
309 Merge COW snapshot LV into its origin.
311 lvconvert --mergesnapshot LV_snapshot ...
313 [ -i|--interval Number ]
314 [ COMMON_OPTIONS ]
315 -
316 Combine a former COW snapshot (second arg) with a former
318 origin LV (first arg) to reverse a splitsnapshot command.
319 lvconvert --type snapshot LV LV_linear_striped
321 [ -s|--snapshot ]
322 [ -c|--chunksize Size[k|UNIT] ]
323 [ -Z|--zero y|n ]
324 [ COMMON_OPTIONS ]
325 -
326 Replace failed PVs in a raid or mirror LV.
328 Repair a thin pool.
329 Repair a cache pool.
330 lvconvert --repair LV_thinpool_cache_cachepool_mirror_raid
332 [ -i|--interval Number ]
333 [ --usepolicies ]
334 [ --poolmetadataspare y|n ]
335 [ COMMON_OPTIONS ]
336 [ PV ... ]
337 -
338 Replace specific PV(s) in a raid LV with another PV.
340 lvconvert --replace PV LV_raid
342 [ COMMON_OPTIONS ]
343 [ PV ... ]
344 -
345 Poll LV to continue conversion.
347 lvconvert --startpoll LV_mirror_raid
349 [ COMMON_OPTIONS ]
350 -
351 Common options for command:
353 [ -b|--background ]
354 [ -f|--force ]
355 [ --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
356 ]
357 [ --noudevsync ]
358 Common options for lvm:
360 [ -d|--debug ]
361 [ -h|--help ]
362 [ -q|--quiet ]
363 [ -t|--test ]
364 [ -v|--verbose ]
365 [ -y|--yes ]
366 [ --commandprofile String ]
367 [ --config String ]
368 [ --driverloaded y|n ]
369 [ --lockopt String ]
370 [ --longhelp ]
371 [ --nolocking ]
372 [ --profile String ]
373 [ --version ]
374
376 --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
377 Determines the allocation policy when a command needs to allo‐
378 cate Physical Extents (PEs) from the VG. Each VG and LV has an
379 allocation policy which can be changed with vgchange/lvchange,
380 or overriden on the command line. normal applies common sense
381 rules such as not placing parallel stripes on the same PV.
382 inherit applies the VG policy to an LV. contiguous requires new
383 PEs be placed adjacent to existing PEs. cling places new PEs on
384 the same PV as existing PEs in the same stripe of the LV. If
385 there are sufficient PEs for an allocation, but normal does not
386 use them, anywhere will use them even if it reduces performance,
387 e.g. by placing two stripes on the same PV. Optional positional
388 PV args on the command line can also be used to limit which PVs
389 the command will use for allocation. See lvm(8) for more infor‐
390 mation about allocation.
391 -b|--background
393 If the operation requires polling, this option causes the com‐
394 mand to return before the operation is complete, and polling is
395 done in the background.
396 -H|--cache
398 Specifies the command is handling a cache LV or cache pool. See
399 --type cache and --type cache-pool. See lvmcache(7) for more
400 information about LVM caching.
401 --cachemetadataformat auto|1|2
403 Specifies the cache metadata format used by cache target.
404 --cachemode writethrough|writeback|passthrough
406 Specifies when writes to a cache LV should be considered com‐
407 plete. writeback considers a write complete as soon as it is
408 stored in the cache pool. writethough considers a write com‐
409 plete only when it has been stored in both the cache pool and on
410 the origin LV. While writethrough may be slower for writes, it
411 is more resilient if something should happen to a device associ‐
412 ated with the cache pool LV. With passthrough, all reads are
413 served from the origin LV (all reads miss the cache) and all
414 writes are forwarded to the origin LV; additionally, write hits
415 cause cache block invalidates. See lvmcache(7) for more informa‐
416 tion.
417 --cachepolicy String
419 Specifies the cache policy for a cache LV. See lvmcache(7) for
420 more information.
421 --cachepool LV
423 The name of a cache pool LV.
424 --cachesettings String
426 Specifies tunable values for a cache LV in "Key = Value" form.
427 Repeat this option to specify multiple values. (The default
428 values should usually be adequate.) The special string value
429 default switches settings back to their default kernel values
430 and removes them from the list of settings stored in LVM meta‐
431 data. See lvmcache(7) for more information.
432 -c|--chunksize Size[k|UNIT]
434 The size of chunks in a snapshot, cache pool or thin pool. For
435 snapshots, the value must be a power of 2 between 4KiB and
436 512KiB and the default value is 4. For a cache pool the value
437 must be between 32KiB and 1GiB and the default value is 64. For
438 a thin pool the value must be between 64KiB and 1GiB and the
439 default value starts with 64 and scales up to fit the pool meta‐
440 data size within 128MiB, if the pool metadata size is not speci‐
441 fied. The value must be a multiple of 64KiB. See lvmthin(7)
442 and lvmcache(7) for more information.
443 --commandprofile String
445 The command profile to use for command configuration. See
446 lvm.conf(5) for more information about profiles.
447 --compression y|n
449 Controls whether compression is enabled or disable for VDO vol‐
450 ume. See lvmvdo(7) for more information about VDO usage.
451 --config String
453 Config settings for the command. These override lvm.conf set‐
454 tings. The String arg uses the same format as lvm.conf, or may
455 use section/field syntax. See lvm.conf(5) for more information
456 about config.
457 -d|--debug ...
459 Set debug level. Repeat from 1 to 6 times to increase the detail
460 of messages sent to the log file and/or syslog (if configured).
461 --deduplication y|n
463 Controls whether deduplication is enabled or disable for VDO
464 volume. See lvmvdo(7) for more information about VDO usage.
465 --discards passdown|nopassdown|ignore
467 Specifies how the device-mapper thin pool layer in the kernel
468 should handle discards. ignore causes the thin pool to ignore
469 discards. nopassdown causes the thin pool to process discards
470 itself to allow reuse of unneeded extents in the thin pool.
471 passdown causes the thin pool to process discards itself (like
472 nopassdown) and pass the discards to the underlying device. See
473 lvmthin(7) for more information.
474 --driverloaded y|n
476 If set to no, the command will not attempt to use device-mapper.
477 For testing and debugging.
478 -f|--force ...
480 Override various checks, confirmations and protections. Use
481 with extreme caution.
482 -h|--help
484 Display help text.
485 -i|--interval Number
487 Report progress at regular intervals.
488 --lockopt String
490 Used to pass options for special cases to lvmlockd. See lvm‐
491 lockd(8) for more information.
492 --longhelp
494 Display long help text.
495 --merge
497 An alias for --mergethin, --mergemirrors, or --mergesnapshot,
498 depending on the type of LV.
499 --mergemirrors
501 Merge LV images that were split from a raid1 LV. See --split‐
502 mirrors with --trackchanges.
503 --mergesnapshot
505 Merge COW snapshot LV into its origin. When merging a snapshot,
506 if both the origin and snapshot LVs are not open, the merge will
507 start immediately. Otherwise, the merge will start the first
508 time either the origin or snapshot LV are activated and both are
509 closed. Merging a snapshot into an origin that cannot be closed,
510 for example a root filesystem, is deferred until the next time
511 the origin volume is activated. When merging starts, the result‐
512 ing LV will have the origin's name, minor number and UUID. While
513 the merge is in progress, reads or writes to the origin appear
514 as being directed to the snapshot being merged. When the merge
515 finishes, the merged snapshot is removed. Multiple snapshots
516 may be specified on the command line or a @tag may be used to
517 specify multiple snapshots be merged to their respective origin.
518 --mergethin
520 Merge thin LV into its origin LV. The origin thin LV takes the
521 content of the thin snapshot, and the thin snapshot LV is
522 removed. See lvmthin(7) for more information.
523 --metadataprofile String
525 The metadata profile to use for command configuration. See
526 lvm.conf(5) for more information about profiles.
527 --mirrorlog core|disk
529 Specifies the type of mirror log for LVs with the "mirror" type
530 (does not apply to the "raid1" type.) disk is a persistent log
531 and requires a small amount of storage space, usually on a sepa‐
532 rate device from the data being mirrored. core is not persis‐
533 tent; the log is kept only in memory. In this case, the mirror
534 must be synchronized (by copying LV data from the first device
535 to others) each time the LV is activated, e.g. after reboot.
536 mirrored is a persistent log that is itself mirrored, but should
537 be avoided. Instead, use the raid1 type for log redundancy.
538 -m|--mirrors [+|-]Number
540 Specifies the number of mirror images in addition to the origi‐
541 nal LV image, e.g. --mirrors 1 means there are two images of the
542 data, the original and one mirror image. Optional positional PV
543 args on the command line can specify the devices the images
544 should be placed on. There are two mirroring implementations:
545 "raid1" and "mirror". These are the names of the corresponding
546 LV types, or "segment types". Use the --type option to specify
547 which to use (raid1 is default, and mirror is legacy) Use
548 lvm.conf global/mirror_segtype_default and global/raid10_seg‐
549 type_default to configure the default types. The plus prefix +
550 can be used, in which case the number is added to the current
551 number of images, or the minus prefix - can be used, in which
552 case the number is subtracted from the current number of images.
553 See lvmraid(7) for more information.
554 -n|--name String
556 Specifies the name of a new LV. When unspecified, a default
557 name of "lvol#" is generated, where # is a number generated by
558 LVM.
559 --nolocking
561 Disable locking.
562 --noudevsync
564 Disables udev synchronisation. The process will not wait for
565 notification from udev. It will continue irrespective of any
566 possible udev processing in the background. Only use this if
567 udev is not running or has rules that ignore the devices LVM
568 creates.
569 --originname LV
571 Specifies the name to use for the external origin LV when con‐
572 verting an LV to a thin LV. The LV being converted becomes a
573 read-only external origin with this name.
574 --poolmetadata LV
576 The name of a an LV to use for storing pool metadata.
577 --poolmetadatasize Size[m|UNIT]
579 Specifies the size of the new pool metadata LV.
580 --poolmetadataspare y|n
582 Enable or disable the automatic creation and management of a
583 spare pool metadata LV in the VG. A spare metadata LV is
584 reserved space that can be used when repairing a pool.
585 --profile String
587 An alias for --commandprofile or --metadataprofile, depending on
588 the command.
589 -q|--quiet ...
591 Suppress output and log messages. Overrides --debug and --ver‐
592 bose. Repeat once to also suppress any prompts with answer
593 'no'.
594 -r|--readahead auto|none|Number
596 Sets read ahead sector count of an LV. auto is the default
597 which allows the kernel to choose a suitable value automati‐
598 cally. none is equivalent to zero.
599 -R|--regionsize Size[m|UNIT]
601 Size of each raid or mirror synchronization region. lvm.conf
602 activation/raid_region_size can be used to configure a default.
603 --repair
605 Replace failed PVs in a raid or mirror LV, or run a repair util‐
606 ity on a thin pool. See lvmraid(7) and lvmthin(7) for more
607 information.
608 --replace PV
610 Replace a specific PV in a raid LV with another PV. The new PV
611 to use can be optionally specified after the LV. Multiple PVs
612 can be replaced by repeating this option. See lvmraid(7) for
613 more information.
614 -s|--snapshot
616 Combine a former COW snapshot LV with a former origin LV to
617 reverse a previous --splitsnapshot command.
618 --splitcache
620 Separates a cache pool from a cache LV, and keeps the unused
621 cache pool LV. Before the separation, the cache is flushed.
622 Also see --uncache.
623 --splitmirrors Number
625 Splits the specified number of images from a raid1 or mirror LV
626 and uses them to create a new LV. If --trackchanges is also
627 specified, changes to the raid1 LV are tracked while the split
628 LV remains detached. If --name is specified, then the images
629 are permanently split from the original LV and changes are not
630 tracked.
631 --splitsnapshot
633 Separates a COW snapshot from its origin LV. The LV that is
634 split off contains the chunks that differ from the origin LV
635 along with metadata describing them. This LV can be wiped and
636 then destroyed with lvremove.
637 --startpoll
639 Start polling an LV to continue processing a conversion.
640 --stripes Number
642 Specifies the number of stripes in a striped LV. This is the
643 number of PVs (devices) that a striped LV is spread across. Data
644 that appears sequential in the LV is spread across multiple
645 devices in units of the stripe size (see --stripesize). This
646 does not apply to existing allocated space, only newly allocated
647 space can be striped.
648 -I|--stripesize Size[k|UNIT]
650 The amount of data that is written to one device before moving
651 to the next in a striped LV.
652 --swapmetadata
654 Extracts the metadata LV from a pool and replaces it with
655 another specified LV. The extracted LV is preserved and given
656 the name of the LV that replaced it. Use for repair only. When
657 the metadata LV is swapped out of the pool, it can be activated
658 directly and used with thin provisioning tools: cache_dump(8),
659 cache_repair(8), cache_restore(8), thin_dump(8), thin_repair(8),
660 thin_restore(8).
661 -t|--test
663 Run in test mode. Commands will not update metadata. This is
664 implemented by disabling all metadata writing but nevertheless
665 returning success to the calling function. This may lead to
666 unusual error messages in multi-stage operations if a tool
667 relies on reading back metadata it believes has changed but
668 hasn't.
669 -T|--thin
671 Specifies the command is handling a thin LV or thin pool. See
672 --type thin, --type thin-pool, and --virtualsize. See
673 lvmthin(7) for more information about LVM thin provisioning.
674 --thinpool LV
676 The name of a thin pool LV.
677 --trackchanges
679 Can be used with --splitmirrors on a raid1 LV. This causes
680 changes to the original raid1 LV to be tracked while the split
681 images remain detached. This is a temporary state that allows
682 the read-only detached image to be merged efficiently back into
683 the raid1 LV later. Only the regions with changed data are
684 resynchronized during merge. While a raid1 LV is tracking
685 changes, operations on it are limited to merging the split image
686 (see --mergemirrors) or permanently splitting the image (see
687 --splitmirrors with --name.
688 --type linear|striped|snapshot|mir‐
690 ror|raid|thin|cache|thin-pool|cache-pool
691 The LV type, also known as "segment type" or "segtype". See
692 usage descriptions for the specific ways to use these types.
693 For more information about redundancy and performance (raid<N>,
694 mirror, striped, linear) see lvmraid(7). For thin provisioning
695 (thin, thin-pool) see lvmthin(7). For performance caching
696 (cache, cache-pool) see lvmcache(7). For copy-on-write snap‐
697 shots (snapshot) see usage definitions. Several commands omit
698 an explicit type option because the type is inferred from other
699 options or shortcuts (e.g. --stripes, --mirrors, --snapshot,
700 --virtualsize, --thin, --cache). Use inferred types with care
701 because it can lead to unexpected results.
702 --uncache
704 Separates a cache pool from a cache LV, and deletes the unused
705 cache pool LV. Before the separation, the cache is flushed.
706 Also see --splitcache.
707 --usepolicies
709 Perform an operation according to the policy configured in
710 lvm.conf or a profile.
711 --vdopool LV
713 The name of a VDO pool LV. See lvmvdo(7) for more information
714 about VDO usage.
715 -v|--verbose ...
717 Set verbose level. Repeat from 1 to 4 times to increase the
718 detail of messages sent to stdout and stderr.
719 --version
721 Display version information.
722 -V|--virtualsize Size[m|UNIT]
724 The virtual size of a new thin LV. See lvmthin(7) for more
725 information about LVM thin provisioning. Using virtual size
726 (-V) and actual size (-L) together creates a sparse LV.
727 lvm.conf global/sparse_segtype_default determines the default
728 segment type used to create a sparse LV. Anything written to a
729 sparse LV will be returned when reading from it. Reading from
730 other areas of the LV will return blocks of zeros. When using a
731 snapshot to create a sparse LV, a hidden virtual device is cre‐
732 ated using the zero target, and the LV has the suffix _vorigin.
733 Snapshots are less efficient than thin provisioning when creat‐
734 ing large sparse LVs (GiB).
735 -y|--yes
737 Do not prompt for confirmation interactively but always assume
738 the answer yes. Use with extreme caution. (For automatic no,
739 see -qq.)
740 -Z|--zero y|n
742 For snapshots, this controls zeroing of the first 4KiB of data
743 in the snapshot. If the LV is read-only, the snapshot will not
744 be zeroed. For thin pools, this controls zeroing of provisioned
745 blocks. Provisioning of large zeroed chunks negatively impacts
746 performance.
747
749 VG
750 Volume Group name. See lvm(8) for valid names.
751 LV
753 Logical Volume name. See lvm(8) for valid names. An LV posi‐
754 tional arg generally includes the VG name and LV name, e.g.
755 VG/LV. LV followed by _<type> indicates that an LV of the given
756 type is required. (raid represents raid<N> type)
757 PV
759 Physical Volume name, a device path under /dev. For commands
760 managing physical extents, a PV positional arg generally accepts
761 a suffix indicating a range (or multiple ranges) of physical
762 extents (PEs). When the first PE is omitted, it defaults to the
763 start of the device, and when the last PE is omitted it defaults
764 to end. Start and end range (inclusive): PV[:PE-PE]... Start
765 and length range (counting from 0): PV[:PE+PE]...
766 Tag
768 Tag name. See lvm(8) for information about tag names and using
769 tags in place of a VG, LV or PV.
770 String
772 See the option description for information about the string con‐
773 tent.
774 Size[UNIT]
776 Size is an input number that accepts an optional unit. Input
777 units are always treated as base two values, regardless of capi‐
778 talization, e.g. 'k' and 'K' both refer to 1024. The default
779 input unit is specified by letter, followed by |UNIT. UNIT rep‐
780 resents other possible input units: bBsSkKmMgGtTpPeE. b|B is
781 bytes, s|S is sectors of 512 bytes, k|K is kilobytes, m|M is
782 megabytes, g|G is gigabytes, t|T is terabytes, p|P is petabytes,
783 e|E is exabytes. (This should not be confused with the output
784 control --units, where capital letters mean multiple of 1000.)
785
787 See lvm(8) for information about environment variables used by lvm.
788 For example, LVM_VG_NAME can generally be substituted for a required VG
789 parameter.
790
792 Alternate command forms, advanced command usage, and listing of all
793 valid syntax for completeness.
794 Convert LV to type mirror (also see type raid1),
796 (also see lvconvert --mirrors).
797 lvconvert --type mirror LV
799 [ -m|--mirrors [+|-]Number ]
800 [ -R|--regionsize Size[m|UNIT] ]
801 [ -i|--interval Number ]
802 [ --mirrorlog core|disk ]
803 [ COMMON_OPTIONS ]
804 [ PV ... ]
805 -
806 Change the region size of an LV.
808 lvconvert -R|--regionsize Size[m|UNIT] LV_raid
810 [ COMMON_OPTIONS ]
811 -
812 Change the type of mirror log used by a mirror LV.
814 lvconvert --mirrorlog core|disk LV_mirror
816 [ COMMON_OPTIONS ]
817 [ PV ... ]
818 -
819 Convert LV to a thin LV, using the original LV as an external origin
821 (infers --type thin).
822 lvconvert -T|--thin --thinpool LV LV_linear_striped_thin_cache_raid
824 [ -r|--readahead auto|none|Number ]
825 [ -c|--chunksize Size[k|UNIT] ]
826 [ -Z|--zero y|n ]
827 [ --type thin ]
828 [ --originname LV_new ]
829 [ --poolmetadata LV ]
830 [ --poolmetadatasize Size[m|UNIT] ]
831 [ --poolmetadataspare y|n ]
832 [ --metadataprofile String ]
833 [ COMMON_OPTIONS ]
834 -
835 Convert LV to type cache (infers --type cache).
837 lvconvert -H|--cache --cachepool LV LV_linear_striped_thinpool_raid
839 [ -Z|--zero y|n ]
840 [ -r|--readahead auto|none|Number ]
841 [ -c|--chunksize Size[k|UNIT] ]
842 [ --type cache ]
843 [ --cachemetadataformat auto|1|2 ]
844 [ --cachemode writethrough|writeback|passthrough ]
845 [ --cachepolicy String ]
846 [ --cachesettings String ]
847 [ --poolmetadata LV ]
848 [ --poolmetadatasize Size[m|UNIT] ]
849 [ --poolmetadataspare y|n ]
850 [ --metadataprofile String ]
851 [ COMMON_OPTIONS ]
852 -
853 Convert LV to type vdopool.
855 lvconvert --vdopool LV_linear_striped_cache_raid
857 [ -n|--name LV_new ]
858 [ -V|--virtualsize Size[m|UNIT] ]
859 [ --type vdo-pool ]
860 [ --compression y|n ]
861 [ --deduplication y|n ]
862 [ COMMON_OPTIONS ]
863 -
864 Separate and delete the cache pool from a cache LV.
866 lvconvert --uncache LV_thinpool_cache
868 [ COMMON_OPTIONS ]
869 -
870 Swap metadata LV in a thin pool or cache pool (for repair only).
872 lvconvert --swapmetadata --poolmetadata LV LV_thinpool_cachepool
874 [ -c|--chunksize Size[k|UNIT] ]
875 [ COMMON_OPTIONS ]
876 -
877 Merge LV that was split from a mirror (variant, use --mergemirrors).
879 Merge thin LV into its origin LV (variant, use --mergethin).
880 Merge COW snapshot LV into its origin (variant, use --mergesnapshot).
881 lvconvert --merge VG|LV_linear_striped_snapshot_thin_raid|Tag ...
883 [ -i|--interval Number ]
884 [ COMMON_OPTIONS ]
885 -
886 Separate a COW snapshot from its origin LV.
888 lvconvert --splitsnapshot LV_snapshot
890 [ COMMON_OPTIONS ]
891 -
892 Combine a former COW snapshot (second arg) with a former
894 origin LV (first arg) to reverse a splitsnapshot command.
895 lvconvert -s|--snapshot LV LV_linear_striped
897 [ -c|--chunksize Size[k|UNIT] ]
898 [ -Z|--zero y|n ]
899 [ --type snapshot ]
900 [ COMMON_OPTIONS ]
901 -
902 Poll LV to continue conversion (also see --startpoll)
904 or waits till conversion/mirror syncing is finished
905 lvconvert LV_mirror_raid
907 [ COMMON_OPTIONS ]
908 -
909
912 This previous command syntax would perform two different operations:
913 lvconvert --thinpool LV1 --poolmetadata LV2
914 If LV1 was not a thin pool, the command would convert LV1 to a thin
915 pool, optionally using a specified LV for metadata. But, if LV1 was
916 already a thin pool, the command would swap the current metadata LV
917 with LV2 (for repair purposes.)
918 In the same way, this previous command syntax would perform two differ‐
920 ent operations:
921 lvconvert --cachepool LV1 --poolmetadata LV2
922 If LV1 was not a cache pool, the command would convert LV1 to a cache
923 pool, optionally using a specified LV for metadata. But, if LV1 was
924 already a cache pool, the command would swap the current metadata LV
925 with LV2 (for repair purposes.)
926
928 Convert a linear LV to a two-way mirror LV.
929 lvconvert --type mirror --mirrors 1 vg/lvol1
930 Convert a linear LV to a two-way RAID1 LV.
932 lvconvert --type raid1 --mirrors 1 vg/lvol1
933 Convert a mirror LV to use an in-memory log.
935 lvconvert --mirrorlog core vg/lvol1
936 Convert a mirror LV to use a disk log.
938 lvconvert --mirrorlog disk vg/lvol1
939 Convert a mirror or raid1 LV to a linear LV.
941 lvconvert --type linear vg/lvol1
942 Convert a mirror LV to a raid1 LV with the same number of images.
944 lvconvert --type raid1 vg/lvol1
945 Convert a linear LV to a two-way mirror LV, allocating new extents from
947 specific PV ranges.
948 lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15
949 Convert a mirror LV to a linear LV, freeing physical extents from a
951 specific PV.
952 lvconvert --type linear vg/lvol1 /dev/sda
953 Split one image from a mirror or raid1 LV, making it a new LV.
955 lvconvert --splitmirrors 1 --name lv_split vg/lvol1
956 Split one image from a raid1 LV, and track changes made to the raid1 LV
958 while the split image remains detached.
959 lvconvert --splitmirrors 1 --trackchanges vg/lvol1
960 Merge an image (that was previously created with --splitmirrors and
962 --trackchanges) back into the original raid1 LV.
963 lvconvert --mergemirrors vg/lvol1_rimage_1
964 Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV.
966 lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1
967 Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV.
969 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1
970 vg/lvol1 /dev/sd[fgh]1
971 Replace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a
973 raid6 LV.
974 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1
975 Convert an LV into a thin LV in the specified thin pool. The existing
977 LV is used as an external read-only origin for the new thin LV.
978 lvconvert --type thin --thinpool vg/tpool1 vg/lvol1
979 Convert an LV into a thin LV in the specified thin pool. The existing
981 LV is used as an external read-only origin for the new thin LV, and is
982 renamed "external".
983 lvconvert --type thin --thinpool vg/tpool1
984 --originname external vg/lvol1
985 Convert an LV to a cache pool LV using another specified LV for cache
987 pool metadata.
988 lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1
989 Convert an LV to a cache LV using the specified cache pool and chunk
991 size.
992 lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1
993 Detach and keep the cache pool from a cache LV.
995 lvconvert --splitcache vg/lvol1
996 Detach and remove the cache pool from a cache LV.
998 lvconvert --uncache vg/lvol1
999
1001 lvm(8) lvm.conf(5) lvmconfig(8)
1002 pvchange(8) pvck(8) pvcreate(8) pvdisplay(8) pvmove(8) pvremove(8)
1004 pvresize(8) pvs(8) pvscan(8)
1005 vgcfgbackup(8) vgcfgrestore(8) vgchange(8) vgck(8) vgcreate(8) vgcon‐
1007 vert(8) vgdisplay(8) vgexport(8) vgextend(8) vgimport(8) vgimport‐
1008 clone(8) vgmerge(8) vgmknodes(8) vgreduce(8) vgremove(8) vgrename(8)
1009 vgs(8) vgscan(8) vgsplit(8)
1010 lvcreate(8) lvchange(8) lvconvert(8) lvdisplay(8) lvextend(8) lvre‐
1012 duce(8) lvremove(8) lvrename(8) lvresize(8) lvs(8) lvscan(8)
1013 lvm-fullreport(8) lvm-lvpoll(8) lvm2-activation-generator(8) blkdeacti‐
1015 vate(8) lvmdump(8)
1016 dmeventd(8) lvmpolld(8) lvmlockd(8) lvmlockctl(8) cmirrord(8) lvmd‐
1018 busd(8)
1019 lvmsystemid(7) lvmreport(7) lvmraid(7) lvmthin(7) lvmcache(7)
1021Red Hat, Inc. LVM TOOLS 2.03.02(2)-RHEL8 (2019-01-04) LVCONVERT(8)