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 --cachevol LV
22 -c|--chunksize Size[k|UNIT]
23 --commandprofile String
24 --compression y|n
25 --config String
26 -d|--debug
27 --deduplication y|n
28 --discards passdown|nopassdown|ignore
29 --driverloaded y|n
30 -f|--force
31 -h|--help
32 -i|--interval Number
33 --lockopt String
34 --longhelp
35 --merge
36 --mergemirrors
37 --mergesnapshot
38 --mergethin
39 --metadataprofile String
40 --mirrorlog core|disk
41 -m|--mirrors [+|-]Number
42 -n|--name String
43 --nolocking
44 --noudevsync
45 --originname LV
46 --poolmetadata LV
47 --poolmetadatasize Size[m|UNIT]
48 --poolmetadataspare y|n
49 --profile String
50 -q|--quiet
51 -r|--readahead auto|none|Number
52 -R|--regionsize Size[m|UNIT]
53 --repair
54 --replace PV
55 -s|--snapshot
56 --splitcache
57 --splitmirrors Number
58 --splitsnapshot
59 --startpoll
60 --stripes Number
61 -I|--stripesize Size[k|UNIT]
62 --swapmetadata
63 -t|--test
64 -T|--thin
65 --thinpool LV
66 --trackchanges
67 --type linear|striped|snapshot|mir‐
68 ror|raid|thin|cache|vdo|thin-pool|cache-pool|vdo-pool
69 --uncache
70 --usepolicies
71 --vdopool LV
72 -v|--verbose
73 --version
74 -V|--virtualsize Size[m|UNIT]
75 -y|--yes
76 -Z|--zero y|n
77
79 lvconvert changes the LV type and includes utilities for LV data main‐
80 tenance. The LV type controls data layout and redundancy. The LV type
81 is also called the segment type or segtype.
82 To display the current LV type, run the command:
84 lvs -o name,segtype LV
86 In some cases, an LV is a single device mapper (dm) layer above physi‐
88 cal devices. In other cases, hidden LVs (dm devices) are layered
89 between the visible LV and physical devices. LVs in the middle layers
90 are called sub LVs. A command run on a visible LV sometimes operates
91 on a sub LV rather than the specified LV. In other cases, a sub LV
92 must be specified directly on the command line.
93 Sub LVs can be displayed with the command:
95 lvs -a
97 The linear type is equivalent to the striped type when one stripe
99 exists. In that case, the types can sometimes be used interchangably.
100 In most cases, the mirror type is deprecated and the raid1 type should
102 be used. They are both implementations of mirroring.
103 Striped raid types are raid0/raid0_meta, raid5 (an alias for raid5_ls),
105 raid6 (an alias for raid6_zr) and raid10 (an alias for raid10_near).
106 As opposed to mirroring, raid5 and raid6 stripe data and calculate par‐
108 ity blocks. The parity blocks can be used for data block recovery in
109 case devices fail. A maximum number of one device in a raid5 LV may
110 fail, and two in case of raid6. Striped raid types typically rotate the
111 parity and data blocks for performance reasons, thus avoiding con‐
112 tention on a single device. Specific arrangements of parity and data
113 blocks (layouts) can be used to optimize I/O performance, or to convert
114 between raid levels. See lvmraid(7) for more information.
115 Layouts of raid5 rotating parity blocks can be: left-asymmetric
117 (raid5_la), left-symmetric (raid5_ls with alias raid5), right-asymmet‐
118 ric (raid5_ra), right-symmetric (raid5_rs) and raid5_n, which doesn't
119 rotate parity blocks. Layouts of raid6 are: zero-restart (raid6_zr with
120 alias raid6), next-restart (raid6_nr), and next-continue (raid6_nc).
121 Layouts including _n allow for conversion between raid levels (raid5_n
123 to raid6 or raid5_n to striped/raid0/raid0_meta). Additionally, special
124 raid6 layouts for raid level conversions between raid5 and raid6 are:
125 raid6_ls_6, raid6_rs_6, raid6_la_6 and raid6_ra_6. Those correspond to
126 their raid5 counterparts (e.g. raid5_rs can be directly converted to
127 raid6_rs_6 and vice-versa).
128 raid10 (an alias for raid10_near) is currently limited to one data copy
130 and even number of sub LVs. This is a mirror group layout, thus a sin‐
131 gle sub LV may fail per mirror group without data loss.
132 Striped raid types support converting the layout, their stripesize and
134 their number of stripes.
135 The striped raid types combined with raid1 allow for conversion from
137 linear-> striped/raid0/raid0_meta and vice-versa by e.g. linear <->
138 raid1 <-> raid5_n (then adding stripes) <-> striped/raid0/raid0_meta.
139
141 Convert LV to linear.
142 lvconvert --type linear LV
144 [ COMMON_OPTIONS ]
145 [ PV ... ]
146 -
147 Convert LV to striped.
149 lvconvert --type striped LV
151 [ -I|--stripesize Size[k|UNIT] ]
152 [ -R|--regionsize Size[m|UNIT] ]
153 [ -i|--interval Number ]
154 [ --stripes Number ]
155 [ COMMON_OPTIONS ]
156 [ PV ... ]
157 -
158 Convert LV to type mirror (also see type raid1),
160 lvconvert --type mirror 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 [ --mirrorlog core|disk ]
168 [ COMMON_OPTIONS ]
169 [ PV ... ]
170 -
171 Convert LV to raid or change raid layout
173 (a specific raid level must be used, e.g. raid1).
174 lvconvert --type raid LV
176 [ -m|--mirrors [+|-]Number ]
177 [ -I|--stripesize Size[k|UNIT] ]
178 [ -R|--regionsize Size[m|UNIT] ]
179 [ -i|--interval Number ]
180 [ --stripes Number ]
181 [ COMMON_OPTIONS ]
182 [ PV ... ]
183 -
184 Convert LV to raid1 or mirror, or change number of mirror images.
186 lvconvert -m|--mirrors [+|-]Number LV
188 [ -R|--regionsize Size[m|UNIT] ]
189 [ -i|--interval Number ]
190 [ --mirrorlog core|disk ]
191 [ COMMON_OPTIONS ]
192 [ PV ... ]
193 -
194 Convert raid LV to change number of stripe images.
196 lvconvert --stripes Number LV_raid
198 [ -i|--interval Number ]
199 [ -R|--regionsize Size[m|UNIT] ]
200 [ -I|--stripesize Size[k|UNIT] ]
201 [ COMMON_OPTIONS ]
202 [ PV ... ]
203 -
204 Convert raid LV to change the stripe size.
206 lvconvert -I|--stripesize Size[k|UNIT] LV_raid
208 [ -i|--interval Number ]
209 [ -R|--regionsize Size[m|UNIT] ]
210 [ COMMON_OPTIONS ]
211 -
212 Split images from a raid1 or mirror LV and use them to create a new LV.
214 lvconvert --splitmirrors Number -n|--name LV_new LV_cache_mirror_raid1
216 [ COMMON_OPTIONS ]
217 [ PV ... ]
218 -
219 Split images from a raid1 LV and track changes to origin for later
221 merge.
222 lvconvert --splitmirrors Number --trackchanges LV_cache_raid1
224 [ COMMON_OPTIONS ]
225 [ PV ... ]
226 -
227 Merge LV images that were split from a raid1 LV.
229 lvconvert --mergemirrors VG|LV_linear_raid|Tag ...
231 [ COMMON_OPTIONS ]
232 -
233 Convert LV to a thin LV, using the original LV as an external origin.
235 lvconvert --type thin --thinpool LV LV_linear_striped_thin_cache_raid
237 [ -T|--thin ]
238 [ -r|--readahead auto|none|Number ]
239 [ -c|--chunksize Size[k|UNIT] ]
240 [ -Z|--zero y|n ]
241 [ --originname LV_new ]
242 [ --poolmetadata LV ]
243 [ --poolmetadatasize Size[m|UNIT] ]
244 [ --poolmetadataspare y|n ]
245 [ --metadataprofile String ]
246 [ COMMON_OPTIONS ]
247 -
248 Attach a cache pool to an LV, converts the LV to type cache.
250 lvconvert --type cache --cachepool LV LV_linear_striped_thin‐
252 pool_vdo_vdopool_vdopooldata_raid
253 [ -H|--cache ]
254 [ -Z|--zero y|n ]
255 [ -r|--readahead auto|none|Number ]
256 [ -c|--chunksize Size[k|UNIT] ]
257 [ --cachemetadataformat auto|1|2 ]
258 [ --cachemode writethrough|writeback|passthrough ]
259 [ --cachepolicy String ]
260 [ --cachesettings String ]
261 [ --poolmetadata LV ]
262 [ --poolmetadatasize Size[m|UNIT] ]
263 [ --poolmetadataspare y|n ]
264 [ --metadataprofile String ]
265 [ COMMON_OPTIONS ]
266 -
267 Attach a writecache to an LV, converts the LV to type writecache.
269 lvconvert --type writecache --cachevol LV LV_linear_striped_raid
271 [ --cachesettings String ]
272 [ COMMON_OPTIONS ]
273 -
274 Attach a cache to an LV, converts the LV to type cache.
276 lvconvert --type cache --cachevol LV LV_linear_striped_thinpool_raid
278 [ -H|--cache ]
279 [ -Z|--zero y|n ]
280 [ -c|--chunksize Size[k|UNIT] ]
281 [ --cachemetadataformat auto|1|2 ]
282 [ --cachemode writethrough|writeback|passthrough ]
283 [ --cachepolicy String ]
284 [ --cachesettings String ]
285 [ --poolmetadatasize Size[m|UNIT] ]
286 [ COMMON_OPTIONS ]
287 -
288 Convert LV to type thin-pool.
290 lvconvert --type thin-pool LV_linear_striped_cache_raid
292 [ -I|--stripesize Size[k|UNIT] ]
293 [ -r|--readahead auto|none|Number ]
294 [ -c|--chunksize Size[k|UNIT] ]
295 [ -Z|--zero y|n ]
296 [ --stripes Number ]
297 [ --discards passdown|nopassdown|ignore ]
298 [ --poolmetadata LV ]
299 [ --poolmetadatasize Size[m|UNIT] ]
300 [ --poolmetadataspare y|n ]
301 [ --metadataprofile String ]
302 [ COMMON_OPTIONS ]
303 [ PV ... ]
304 -
305 Convert LV to type cache-pool.
307 lvconvert --type cache-pool LV_linear_striped_raid
309 [ -Z|--zero y|n ]
310 [ -r|--readahead auto|none|Number ]
311 [ -c|--chunksize Size[k|UNIT] ]
312 [ --cachemetadataformat auto|1|2 ]
313 [ --cachemode writethrough|writeback|passthrough ]
314 [ --cachepolicy String ]
315 [ --cachesettings String ]
316 [ --poolmetadata LV ]
317 [ --poolmetadatasize Size[m|UNIT] ]
318 [ --poolmetadataspare y|n ]
319 [ --metadataprofile String ]
320 [ COMMON_OPTIONS ]
321 [ PV ... ]
322 -
323 Convert LV to type vdopool.
325 lvconvert --type vdo-pool LV_linear_striped_cache_raid
327 [ -n|--name LV_new ]
328 [ -V|--virtualsize Size[m|UNIT] ]
329 [ --compression y|n ]
330 [ --deduplication y|n ]
331 [ COMMON_OPTIONS ]
332 -
333 Detach a cache from an LV.
335 lvconvert --splitcache LV_thinpool_cache_cachepool_vdopool_writecache
337 [ COMMON_OPTIONS ]
338 -
339 Merge thin LV into its origin LV.
341 lvconvert --mergethin LV_thin ...
343 [ COMMON_OPTIONS ]
344 -
345 Merge COW snapshot LV into its origin.
347 lvconvert --mergesnapshot LV_snapshot ...
349 [ -i|--interval Number ]
350 [ COMMON_OPTIONS ]
351 -
352 Combine a former COW snapshot (second arg) with a former
354 origin LV (first arg) to reverse a splitsnapshot command.
355 lvconvert --type snapshot LV LV_linear_striped
357 [ -s|--snapshot ]
358 [ -c|--chunksize Size[k|UNIT] ]
359 [ -Z|--zero y|n ]
360 [ COMMON_OPTIONS ]
361 -
362 Replace failed PVs in a raid or mirror LV.
364 Repair a thin pool.
365 Repair a cache pool.
366 lvconvert --repair LV_thinpool_cache_cachepool_mirror_raid
368 [ -i|--interval Number ]
369 [ --usepolicies ]
370 [ --poolmetadataspare y|n ]
371 [ COMMON_OPTIONS ]
372 [ PV ... ]
373 -
374 Replace specific PV(s) in a raid LV with another PV.
376 lvconvert --replace PV LV_raid
378 [ COMMON_OPTIONS ]
379 [ PV ... ]
380 -
381 Poll LV to continue conversion.
383 lvconvert --startpoll LV_mirror_raid
385 [ COMMON_OPTIONS ]
386 -
387 Common options for command:
389 [ -b|--background ]
390 [ -f|--force ]
391 [ --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
392 ]
393 [ --noudevsync ]
394 Common options for lvm:
396 [ -d|--debug ]
397 [ -h|--help ]
398 [ -q|--quiet ]
399 [ -t|--test ]
400 [ -v|--verbose ]
401 [ -y|--yes ]
402 [ --commandprofile String ]
403 [ --config String ]
404 [ --driverloaded y|n ]
405 [ --lockopt String ]
406 [ --longhelp ]
407 [ --nolocking ]
408 [ --profile String ]
409 [ --version ]
410
412 --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
413 Determines the allocation policy when a command needs to allo‐
414 cate Physical Extents (PEs) from the VG. Each VG and LV has an
415 allocation policy which can be changed with vgchange/lvchange,
416 or overriden on the command line. normal applies common sense
417 rules such as not placing parallel stripes on the same PV.
418 inherit applies the VG policy to an LV. contiguous requires new
419 PEs be placed adjacent to existing PEs. cling places new PEs on
420 the same PV as existing PEs in the same stripe of the LV. If
421 there are sufficient PEs for an allocation, but normal does not
422 use them, anywhere will use them even if it reduces performance,
423 e.g. by placing two stripes on the same PV. Optional positional
424 PV args on the command line can also be used to limit which PVs
425 the command will use for allocation. See lvm(8) for more infor‐
426 mation about allocation.
427 -b|--background
429 If the operation requires polling, this option causes the com‐
430 mand to return before the operation is complete, and polling is
431 done in the background.
432 -H|--cache
434 Specifies the command is handling a cache LV or cache pool. See
435 --type cache and --type cache-pool. See lvmcache(7) for more
436 information about LVM caching.
437 --cachemetadataformat auto|1|2
439 Specifies the cache metadata format used by cache target.
440 --cachemode writethrough|writeback|passthrough
442 Specifies when writes to a cache LV should be considered com‐
443 plete. writeback considers a write complete as soon as it is
444 stored in the cache pool. writethough considers a write com‐
445 plete only when it has been stored in both the cache pool and on
446 the origin LV. While writethrough may be slower for writes, it
447 is more resilient if something should happen to a device associ‐
448 ated with the cache pool LV. With passthrough, all reads are
449 served from the origin LV (all reads miss the cache) and all
450 writes are forwarded to the origin LV; additionally, write hits
451 cause cache block invalidates. See lvmcache(7) for more informa‐
452 tion.
453 --cachepolicy String
455 Specifies the cache policy for a cache LV. See lvmcache(7) for
456 more information.
457 --cachepool LV
459 The name of a cache pool.
460 --cachesettings String
462 Specifies tunable values for a cache LV in "Key = Value" form.
463 Repeat this option to specify multiple values. (The default
464 values should usually be adequate.) The special string value
465 default switches settings back to their default kernel values
466 and removes them from the list of settings stored in LVM meta‐
467 data. See lvmcache(7) for more information.
468 --cachevol LV
470 The name of a cache volume.
471 -c|--chunksize Size[k|UNIT]
473 The size of chunks in a snapshot, cache pool or thin pool. For
474 snapshots, the value must be a power of 2 between 4KiB and
475 512KiB and the default value is 4. For a cache pool the value
476 must be between 32KiB and 1GiB and the default value is 64. For
477 a thin pool the value must be between 64KiB and 1GiB and the
478 default value starts with 64 and scales up to fit the pool meta‐
479 data size within 128MiB, if the pool metadata size is not speci‐
480 fied. The value must be a multiple of 64KiB. See lvmthin(7)
481 and lvmcache(7) for more information.
482 --commandprofile String
484 The command profile to use for command configuration. See
485 lvm.conf(5) for more information about profiles.
486 --compression y|n
488 Controls whether compression is enabled or disable for VDO vol‐
489 ume. See lvmvdo(7) for more information about VDO usage.
490 --config String
492 Config settings for the command. These override lvm.conf set‐
493 tings. The String arg uses the same format as lvm.conf, or may
494 use section/field syntax. See lvm.conf(5) for more information
495 about config.
496 -d|--debug ...
498 Set debug level. Repeat from 1 to 6 times to increase the detail
499 of messages sent to the log file and/or syslog (if configured).
500 --deduplication y|n
502 Controls whether deduplication is enabled or disable for VDO
503 volume. See lvmvdo(7) for more information about VDO usage.
504 --discards passdown|nopassdown|ignore
506 Specifies how the device-mapper thin pool layer in the kernel
507 should handle discards. ignore causes the thin pool to ignore
508 discards. nopassdown causes the thin pool to process discards
509 itself to allow reuse of unneeded extents in the thin pool.
510 passdown causes the thin pool to process discards itself (like
511 nopassdown) and pass the discards to the underlying device. See
512 lvmthin(7) for more information.
513 --driverloaded y|n
515 If set to no, the command will not attempt to use device-mapper.
516 For testing and debugging.
517 -f|--force ...
519 Override various checks, confirmations and protections. Use
520 with extreme caution.
521 -h|--help
523 Display help text.
524 -i|--interval Number
526 Report progress at regular intervals.
527 --lockopt String
529 Used to pass options for special cases to lvmlockd. See lvm‐
530 lockd(8) for more information.
531 --longhelp
533 Display long help text.
534 --merge
536 An alias for --mergethin, --mergemirrors, or --mergesnapshot,
537 depending on the type of LV.
538 --mergemirrors
540 Merge LV images that were split from a raid1 LV. See --split‐
541 mirrors with --trackchanges.
542 --mergesnapshot
544 Merge COW snapshot LV into its origin. When merging a snapshot,
545 if both the origin and snapshot LVs are not open, the merge will
546 start immediately. Otherwise, the merge will start the first
547 time either the origin or snapshot LV are activated and both are
548 closed. Merging a snapshot into an origin that cannot be closed,
549 for example a root filesystem, is deferred until the next time
550 the origin volume is activated. When merging starts, the result‐
551 ing LV will have the origin's name, minor number and UUID. While
552 the merge is in progress, reads or writes to the origin appear
553 as being directed to the snapshot being merged. When the merge
554 finishes, the merged snapshot is removed. Multiple snapshots
555 may be specified on the command line or a @tag may be used to
556 specify multiple snapshots be merged to their respective origin.
557 --mergethin
559 Merge thin LV into its origin LV. The origin thin LV takes the
560 content of the thin snapshot, and the thin snapshot LV is
561 removed. See lvmthin(7) for more information.
562 --metadataprofile String
564 The metadata profile to use for command configuration. See
565 lvm.conf(5) for more information about profiles.
566 --mirrorlog core|disk
568 Specifies the type of mirror log for LVs with the "mirror" type
569 (does not apply to the "raid1" type.) disk is a persistent log
570 and requires a small amount of storage space, usually on a sepa‐
571 rate device from the data being mirrored. core is not persis‐
572 tent; the log is kept only in memory. In this case, the mirror
573 must be synchronized (by copying LV data from the first device
574 to others) each time the LV is activated, e.g. after reboot.
575 mirrored is a persistent log that is itself mirrored, but should
576 be avoided. Instead, use the raid1 type for log redundancy.
577 -m|--mirrors [+|-]Number
579 Specifies the number of mirror images in addition to the origi‐
580 nal LV image, e.g. --mirrors 1 means there are two images of the
581 data, the original and one mirror image. Optional positional PV
582 args on the command line can specify the devices the images
583 should be placed on. There are two mirroring implementations:
584 "raid1" and "mirror". These are the names of the corresponding
585 LV types, or "segment types". Use the --type option to specify
586 which to use (raid1 is default, and mirror is legacy) Use
587 lvm.conf global/mirror_segtype_default and global/raid10_seg‐
588 type_default to configure the default types. The plus prefix +
589 can be used, in which case the number is added to the current
590 number of images, or the minus prefix - can be used, in which
591 case the number is subtracted from the current number of images.
592 See lvmraid(7) for more information.
593 -n|--name String
595 Specifies the name of a new LV. When unspecified, a default
596 name of "lvol#" is generated, where # is a number generated by
597 LVM.
598 --nolocking
600 Disable locking.
601 --noudevsync
603 Disables udev synchronisation. The process will not wait for
604 notification from udev. It will continue irrespective of any
605 possible udev processing in the background. Only use this if
606 udev is not running or has rules that ignore the devices LVM
607 creates.
608 --originname LV
610 Specifies the name to use for the external origin LV when con‐
611 verting an LV to a thin LV. The LV being converted becomes a
612 read-only external origin with this name.
613 --poolmetadata LV
615 The name of a an LV to use for storing pool metadata.
616 --poolmetadatasize Size[m|UNIT]
618 Specifies the size of the new pool metadata LV.
619 --poolmetadataspare y|n
621 Enable or disable the automatic creation and management of a
622 spare pool metadata LV in the VG. A spare metadata LV is
623 reserved space that can be used when repairing a pool.
624 --profile String
626 An alias for --commandprofile or --metadataprofile, depending on
627 the command.
628 -q|--quiet ...
630 Suppress output and log messages. Overrides --debug and --ver‐
631 bose. Repeat once to also suppress any prompts with answer
632 'no'.
633 -r|--readahead auto|none|Number
635 Sets read ahead sector count of an LV. auto is the default
636 which allows the kernel to choose a suitable value automati‐
637 cally. none is equivalent to zero.
638 -R|--regionsize Size[m|UNIT]
640 Size of each raid or mirror synchronization region. lvm.conf
641 activation/raid_region_size can be used to configure a default.
642 --repair
644 Replace failed PVs in a raid or mirror LV, or run a repair util‐
645 ity on a thin pool. See lvmraid(7) and lvmthin(7) for more
646 information.
647 --replace PV
649 Replace a specific PV in a raid LV with another PV. The new PV
650 to use can be optionally specified after the LV. Multiple PVs
651 can be replaced by repeating this option. See lvmraid(7) for
652 more information.
653 -s|--snapshot
655 Combine a former COW snapshot LV with a former origin LV to
656 reverse a previous --splitsnapshot command.
657 --splitcache
659 Separates a cache pool from a cache LV, and keeps the unused
660 cache pool LV. Before the separation, the cache is flushed.
661 Also see --uncache.
662 --splitmirrors Number
664 Splits the specified number of images from a raid1 or mirror LV
665 and uses them to create a new LV. If --trackchanges is also
666 specified, changes to the raid1 LV are tracked while the split
667 LV remains detached. If --name is specified, then the images
668 are permanently split from the original LV and changes are not
669 tracked.
670 --splitsnapshot
672 Separates a COW snapshot from its origin LV. The LV that is
673 split off contains the chunks that differ from the origin LV
674 along with metadata describing them. This LV can be wiped and
675 then destroyed with lvremove.
676 --startpoll
678 Start polling an LV to continue processing a conversion.
679 --stripes Number
681 Specifies the number of stripes in a striped LV. This is the
682 number of PVs (devices) that a striped LV is spread across. Data
683 that appears sequential in the LV is spread across multiple
684 devices in units of the stripe size (see --stripesize). This
685 does not apply to existing allocated space, only newly allocated
686 space can be striped.
687 -I|--stripesize Size[k|UNIT]
689 The amount of data that is written to one device before moving
690 to the next in a striped LV.
691 --swapmetadata
693 Extracts the metadata LV from a pool and replaces it with
694 another specified LV. The extracted LV is preserved and given
695 the name of the LV that replaced it. Use for repair only. When
696 the metadata LV is swapped out of the pool, it can be activated
697 directly and used with thin provisioning tools: cache_dump(8),
698 cache_repair(8), cache_restore(8), thin_dump(8), thin_repair(8),
699 thin_restore(8).
700 -t|--test
702 Run in test mode. Commands will not update metadata. This is
703 implemented by disabling all metadata writing but nevertheless
704 returning success to the calling function. This may lead to
705 unusual error messages in multi-stage operations if a tool
706 relies on reading back metadata it believes has changed but
707 hasn't.
708 -T|--thin
710 Specifies the command is handling a thin LV or thin pool. See
711 --type thin, --type thin-pool, and --virtualsize. See
712 lvmthin(7) for more information about LVM thin provisioning.
713 --thinpool LV
715 The name of a thin pool LV.
716 --trackchanges
718 Can be used with --splitmirrors on a raid1 LV. This causes
719 changes to the original raid1 LV to be tracked while the split
720 images remain detached. This is a temporary state that allows
721 the read-only detached image to be merged efficiently back into
722 the raid1 LV later. Only the regions with changed data are
723 resynchronized during merge. While a raid1 LV is tracking
724 changes, operations on it are limited to merging the split image
725 (see --mergemirrors) or permanently splitting the image (see
726 --splitmirrors with --name.
727 --type linear|striped|snapshot|mir‐
729 ror|raid|thin|cache|vdo|thin-pool|cache-pool|vdo-pool
730 The LV type, also known as "segment type" or "segtype". See
731 usage descriptions for the specific ways to use these types.
732 For more information about redundancy and performance (raid<N>,
733 mirror, striped, linear) see lvmraid(7). For thin provisioning
734 (thin, thin-pool) see lvmthin(7). For performance caching
735 (cache, cache-pool) see lvmcache(7). For copy-on-write snap‐
736 shots (snapshot) see usage definitions. For VDO (vdo) see
737 lvmvdo(7). Several commands omit an explicit type option
738 because the type is inferred from other options or shortcuts
739 (e.g. --stripes, --mirrors, --snapshot, --virtualsize, --thin,
740 --cache, --vdo). Use inferred types with care because it can
741 lead to unexpected results.
742 --uncache
744 Separates a cache pool from a cache LV, and deletes the unused
745 cache pool LV. Before the separation, the cache is flushed.
746 Also see --splitcache.
747 --usepolicies
749 Perform an operation according to the policy configured in
750 lvm.conf or a profile.
751 --vdopool LV
753 The name of a VDO pool LV. See lvmvdo(7) for more information
754 about VDO usage.
755 -v|--verbose ...
757 Set verbose level. Repeat from 1 to 4 times to increase the
758 detail of messages sent to stdout and stderr.
759 --version
761 Display version information.
762 -V|--virtualsize Size[m|UNIT]
764 The virtual size of a new thin LV. See lvmthin(7) for more
765 information about LVM thin provisioning. Using virtual size
766 (-V) and actual size (-L) together creates a sparse LV.
767 lvm.conf global/sparse_segtype_default determines the default
768 segment type used to create a sparse LV. Anything written to a
769 sparse LV will be returned when reading from it. Reading from
770 other areas of the LV will return blocks of zeros. When using a
771 snapshot to create a sparse LV, a hidden virtual device is cre‐
772 ated using the zero target, and the LV has the suffix _vorigin.
773 Snapshots are less efficient than thin provisioning when creat‐
774 ing large sparse LVs (GiB).
775 -y|--yes
777 Do not prompt for confirmation interactively but always assume
778 the answer yes. Use with extreme caution. (For automatic no,
779 see -qq.)
780 -Z|--zero y|n
782 For snapshots, this controls zeroing of the first 4KiB of data
783 in the snapshot. If the LV is read-only, the snapshot will not
784 be zeroed. For thin pools, this controls zeroing of provisioned
785 blocks. Provisioning of large zeroed chunks negatively impacts
786 performance.
787
789 VG
790 Volume Group name. See lvm(8) for valid names.
791 LV
793 Logical Volume name. See lvm(8) for valid names. An LV posi‐
794 tional arg generally includes the VG name and LV name, e.g.
795 VG/LV. LV followed by _<type> indicates that an LV of the given
796 type is required. (raid represents raid<N> type)
797 PV
799 Physical Volume name, a device path under /dev. For commands
800 managing physical extents, a PV positional arg generally accepts
801 a suffix indicating a range (or multiple ranges) of physical
802 extents (PEs). When the first PE is omitted, it defaults to the
803 start of the device, and when the last PE is omitted it defaults
804 to end. Start and end range (inclusive): PV[:PE-PE]... Start
805 and length range (counting from 0): PV[:PE+PE]...
806 Tag
808 Tag name. See lvm(8) for information about tag names and using
809 tags in place of a VG, LV or PV.
810 String
812 See the option description for information about the string con‐
813 tent.
814 Size[UNIT]
816 Size is an input number that accepts an optional unit. Input
817 units are always treated as base two values, regardless of capi‐
818 talization, e.g. 'k' and 'K' both refer to 1024. The default
819 input unit is specified by letter, followed by |UNIT. UNIT rep‐
820 resents other possible input units: bBsSkKmMgGtTpPeE. b|B is
821 bytes, s|S is sectors of 512 bytes, k|K is kilobytes, m|M is
822 megabytes, g|G is gigabytes, t|T is terabytes, p|P is petabytes,
823 e|E is exabytes. (This should not be confused with the output
824 control --units, where capital letters mean multiple of 1000.)
825
827 See lvm(8) for information about environment variables used by lvm.
828 For example, LVM_VG_NAME can generally be substituted for a required VG
829 parameter.
830
832 Alternate command forms, advanced command usage, and listing of all
833 valid syntax for completeness.
834 Change the region size of an LV.
836 lvconvert -R|--regionsize Size[m|UNIT] LV_raid
838 [ COMMON_OPTIONS ]
839 -
840 Change the type of mirror log used by a mirror LV.
842 lvconvert --mirrorlog core|disk LV_mirror
844 [ COMMON_OPTIONS ]
845 [ PV ... ]
846 -
847 Convert LV to a thin LV, using the original LV as an external origin
849 (infers --type thin).
850 lvconvert -T|--thin --thinpool LV LV_linear_striped_thin_cache_raid
852 [ -r|--readahead auto|none|Number ]
853 [ -c|--chunksize Size[k|UNIT] ]
854 [ -Z|--zero y|n ]
855 [ --type thin ]
856 [ --originname LV_new ]
857 [ --poolmetadata LV ]
858 [ --poolmetadatasize Size[m|UNIT] ]
859 [ --poolmetadataspare y|n ]
860 [ --metadataprofile String ]
861 [ COMMON_OPTIONS ]
862 -
863 Attach a cache pool to an LV (infers --type cache).
865 lvconvert -H|--cache --cachepool LV LV_linear_striped_thin‐
867 pool_vdo_vdopool_vdopooldata_raid
868 [ -Z|--zero y|n ]
869 [ -r|--readahead auto|none|Number ]
870 [ -c|--chunksize Size[k|UNIT] ]
871 [ --type cache ]
872 [ --cachemetadataformat auto|1|2 ]
873 [ --cachemode writethrough|writeback|passthrough ]
874 [ --cachepolicy String ]
875 [ --cachesettings String ]
876 [ --poolmetadata LV ]
877 [ --poolmetadatasize Size[m|UNIT] ]
878 [ --poolmetadataspare y|n ]
879 [ --metadataprofile String ]
880 [ COMMON_OPTIONS ]
881 -
882 Attach a cache to an LV, converts the LV to type cache.
884 lvconvert -H|--cache --cachevol LV LV_linear_striped_thinpool_raid
886 [ -Z|--zero y|n ]
887 [ -c|--chunksize Size[k|UNIT] ]
888 [ --cachemetadataformat auto|1|2 ]
889 [ --cachemode writethrough|writeback|passthrough ]
890 [ --cachepolicy String ]
891 [ --cachesettings String ]
892 [ --poolmetadatasize Size[m|UNIT] ]
893 [ COMMON_OPTIONS ]
894 -
895 Convert LV to type vdopool.
897 lvconvert --vdopool LV_linear_striped_cache_raid
899 [ -n|--name LV_new ]
900 [ -V|--virtualsize Size[m|UNIT] ]
901 [ --type vdo-pool ]
902 [ --compression y|n ]
903 [ --deduplication y|n ]
904 [ COMMON_OPTIONS ]
905 -
906 Detach and delete a cache from an LV.
908 lvconvert --uncache LV_thinpool_cache_vdopool_writecache
910 [ COMMON_OPTIONS ]
911 -
912 Swap metadata LV in a thin pool or cache pool (for repair only).
914 lvconvert --swapmetadata --poolmetadata LV LV_thinpool_cachepool
916 [ -c|--chunksize Size[k|UNIT] ]
917 [ COMMON_OPTIONS ]
918 -
919 Merge LV that was split from a mirror (variant, use --mergemirrors).
921 Merge thin LV into its origin LV (variant, use --mergethin).
922 Merge COW snapshot LV into its origin (variant, use --mergesnapshot).
923 lvconvert --merge VG|LV_linear_striped_snapshot_thin_raid|Tag ...
925 [ -i|--interval Number ]
926 [ COMMON_OPTIONS ]
927 -
928 Separate a COW snapshot from its origin LV.
930 lvconvert --splitsnapshot LV_snapshot
932 [ COMMON_OPTIONS ]
933 -
934 Combine a former COW snapshot (second arg) with a former
936 origin LV (first arg) to reverse a splitsnapshot command.
937 lvconvert -s|--snapshot LV LV_linear_striped
939 [ -c|--chunksize Size[k|UNIT] ]
940 [ -Z|--zero y|n ]
941 [ --type snapshot ]
942 [ COMMON_OPTIONS ]
943 -
944 Poll LV to continue conversion (also see --startpoll)
946 or waits till conversion/mirror syncing is finished
947 lvconvert LV_mirror_raid
949 [ COMMON_OPTIONS ]
950 -
951
954 This previous command syntax would perform two different operations:
955 lvconvert --thinpool LV1 --poolmetadata LV2
956 If LV1 was not a thin pool, the command would convert LV1 to a thin
957 pool, optionally using a specified LV for metadata. But, if LV1 was
958 already a thin pool, the command would swap the current metadata LV
959 with LV2 (for repair purposes.)
960 In the same way, this previous command syntax would perform two differ‐
962 ent operations:
963 lvconvert --cachepool LV1 --poolmetadata LV2
964 If LV1 was not a cache pool, the command would convert LV1 to a cache
965 pool, optionally using a specified LV for metadata. But, if LV1 was
966 already a cache pool, the command would swap the current metadata LV
967 with LV2 (for repair purposes.)
968
970 Convert a linear LV to a two-way mirror LV.
971 lvconvert --type mirror --mirrors 1 vg/lvol1
972 Convert a linear LV to a two-way RAID1 LV.
974 lvconvert --type raid1 --mirrors 1 vg/lvol1
975 Convert a mirror LV to use an in-memory log.
977 lvconvert --mirrorlog core vg/lvol1
978 Convert a mirror LV to use a disk log.
980 lvconvert --mirrorlog disk vg/lvol1
981 Convert a mirror or raid1 LV to a linear LV.
983 lvconvert --type linear vg/lvol1
984 Convert a mirror LV to a raid1 LV with the same number of images.
986 lvconvert --type raid1 vg/lvol1
987 Convert a linear LV to a two-way mirror LV, allocating new extents from
989 specific PV ranges.
990 lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15
991 Convert a mirror LV to a linear LV, freeing physical extents from a
993 specific PV.
994 lvconvert --type linear vg/lvol1 /dev/sda
995 Split one image from a mirror or raid1 LV, making it a new LV.
997 lvconvert --splitmirrors 1 --name lv_split vg/lvol1
998 Split one image from a raid1 LV, and track changes made to the raid1 LV
1000 while the split image remains detached.
1001 lvconvert --splitmirrors 1 --trackchanges vg/lvol1
1002 Merge an image (that was previously created with --splitmirrors and
1004 --trackchanges) back into the original raid1 LV.
1005 lvconvert --mergemirrors vg/lvol1_rimage_1
1006 Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV.
1008 lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1
1009 Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV.
1011 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1
1012 vg/lvol1 /dev/sd[fgh]1
1013 Replace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a
1015 raid6 LV.
1016 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1
1017 Convert an LV into a thin LV in the specified thin pool. The existing
1019 LV is used as an external read-only origin for the new thin LV.
1020 lvconvert --type thin --thinpool vg/tpool1 vg/lvol1
1021 Convert an LV into a thin LV in the specified thin pool. The existing
1023 LV is used as an external read-only origin for the new thin LV, and is
1024 renamed "external".
1025 lvconvert --type thin --thinpool vg/tpool1
1026 --originname external vg/lvol1
1027 Convert an LV to a cache pool LV using another specified LV for cache
1029 pool metadata.
1030 lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1
1031 Convert an LV to a cache LV using the specified cache pool and chunk
1033 size.
1034 lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1
1035 Detach and keep the cache pool from a cache LV.
1037 lvconvert --splitcache vg/lvol1
1038 Detach and remove the cache pool from a cache LV.
1040 lvconvert --uncache vg/lvol1
1041
1043 lvm(8) lvm.conf(5) lvmconfig(8)
1044 pvchange(8) pvck(8) pvcreate(8) pvdisplay(8) pvmove(8) pvremove(8)
1046 pvresize(8) pvs(8) pvscan(8)
1047 vgcfgbackup(8) vgcfgrestore(8) vgchange(8) vgck(8) vgcreate(8) vgcon‐
1049 vert(8) vgdisplay(8) vgexport(8) vgextend(8) vgimport(8) vgimport‐
1050 clone(8) vgmerge(8) vgmknodes(8) vgreduce(8) vgremove(8) vgrename(8)
1051 vgs(8) vgscan(8) vgsplit(8)
1052 lvcreate(8) lvchange(8) lvconvert(8) lvdisplay(8) lvextend(8) lvre‐
1054 duce(8) lvremove(8) lvrename(8) lvresize(8) lvs(8) lvscan(8)
1055 lvm-fullreport(8) lvm-lvpoll(8) lvm2-activation-generator(8) blkdeacti‐
1057 vate(8) lvmdump(8)
1058 dmeventd(8) lvmpolld(8) lvmlockd(8) lvmlockctl(8) cmirrord(8) lvmd‐
1060 busd(8)
1061 lvmsystemid(7) lvmreport(7) lvmraid(7) lvmthin(7) lvmcache(7)
1063Red Hat, Inc. LVM TOOLS 2.03.06(2) (2019-10-23) LVCONVERT(8)