1LVCONVERT(8)                System Manager's Manual               LVCONVERT(8)
2
3
4

NAME

6       lvconvert - Change logical volume layout
7

SYNOPSIS

9       lvconvert option_args position_args
10           [ option_args ]
11           [ position_args ]
12
13           --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           --config String
24        -d|--debug
25           --discards passdown|nopassdown|ignore
26           --driverloaded y|n
27        -f|--force
28        -h|--help
29        -i|--interval Number
30           --lockopt String
31           --longhelp
32           --merge
33           --mergemirrors
34           --mergesnapshot
35           --mergethin
36           --metadataprofile String
37           --mirrorlog core|disk
38        -m|--mirrors [+|-]Number
39        -n|--name String
40           --noudevsync
41           --originname LV
42           --poolmetadata LV
43           --poolmetadatasize Size[m|UNIT]
44           --poolmetadataspare y|n
45           --profile String
46        -q|--quiet
47        -r|--readahead auto|none|Number
48        -R|--regionsize Size[m|UNIT]
49           --repair
50           --replace PV
51        -s|--snapshot
52           --splitcache
53           --splitmirrors Number
54           --splitsnapshot
55           --startpoll
56           --stripes Number
57        -I|--stripesize Size[k|UNIT]
58           --swapmetadata
59        -t|--test
60        -T|--thin
61           --thinpool LV
62           --trackchanges
63           --type linear|striped|snapshot|mir‐
64       ror|raid|thin|cache|thin-pool|cache-pool
65           --uncache
66           --usepolicies
67        -v|--verbose
68           --version
69        -y|--yes
70        -Z|--zero y|n
71

DESCRIPTION

73       lvconvert changes the LV type and includes utilities for LV data  main‐
74       tenance.  The LV type controls data layout and redundancy.  The LV type
75       is also called the segment type or segtype.
76
77       To display the current LV type, run the command:
78
79       lvs -o name,segtype LV
80
81       In some cases, an LV is a single device mapper (dm) layer above  physi‐
82       cal  devices.   In  other  cases,  hidden  LVs (dm devices) are layered
83       between the visible LV and physical devices.  LVs in the middle  layers
84       are  called  sub LVs.  A command run on a visible LV sometimes operates
85       on a sub LV rather than the specified LV.  In other  cases,  a  sub  LV
86       must be specified directly on the command line.
87
88       Sub LVs can be displayed with the command:
89
90       lvs -a
91
92       The  linear  type  is  equivalent  to  the striped type when one stripe
93       exists.  In that case, the types can sometimes be used interchangably.
94
95       In most cases, the mirror type is deprecated and the raid1 type  should
96       be used.  They are both implementations of mirroring.
97
98       Striped raid types are raid0/raid0_meta, raid5 (an alias for raid5_ls),
99       raid6 (an alias for raid6_zr) and raid10 (an alias for raid10_near).
100
101       As opposed to mirroring, raid5 and raid6 stripe data and calculate par‐
102       ity  blocks.  The  parity blocks can be used for data block recovery in
103       case devices fail. A maximum number of one device in  a  raid5  LV  may
104       fail, and two in case of raid6. Striped raid types typically rotate the
105       parity and data blocks for  performance  reasons,  thus  avoiding  con‐
106       tention  on  a  single device. Specific arrangements of parity and data
107       blocks (layouts) can be used to optimize I/O performance, or to convert
108       between raid levels.  See lvmraid(7) for more information.
109
110       Layouts  of  raid5  rotating  parity  blocks  can  be:  left-asymmetric
111       (raid5_la), left-symmetric (raid5_ls with alias raid5),  right-asymmet‐
112       ric  (raid5_ra),  right-symmetric (raid5_rs) and raid5_n, which doesn't
113       rotate parity blocks. Layouts of raid6 are: zero-restart (raid6_zr with
114       alias raid6), next-restart (raid6_nr), and next-continue (raid6_nc).
115
116       Layouts  including _n allow for conversion between raid levels (raid5_n
117       to raid6 or raid5_n to striped/raid0/raid0_meta). Additionally, special
118       raid6  layouts  for raid level conversions between raid5 and raid6 are:
119       raid6_ls_6, raid6_rs_6, raid6_la_6 and raid6_ra_6. Those correspond  to
120       their  raid5  counterparts  (e.g. raid5_rs can be directly converted to
121       raid6_rs_6 and vice-versa).
122
123       raid10 (an alias for raid10_near) is currently limited to one data copy
124       and  even number of sub LVs. This is a mirror group layout, thus a sin‐
125       gle sub LV may fail per mirror group without data loss.
126
127       Striped raid types support converting the layout, their stripesize  and
128       their number of stripes.
129
130       The  striped  raid  types combined with raid1 allow for conversion from
131       linear-> striped/raid0/raid0_meta and vice-versa  by  e.g.  linear  <->
132       raid1 <-> raid5_n (then adding stripes) <-> striped/raid0/raid0_meta.
133

USAGE

135       Convert LV to linear.
136
137       lvconvert --type linear LV
138           [ COMMON_OPTIONS ]
139           [ PV ... ]
140       -
141
142       Convert LV to striped.
143
144       lvconvert --type striped LV
145           [ -I|--stripesize Size[k|UNIT] ]
146           [ -R|--regionsize Size[m|UNIT] ]
147           [ -i|--interval Number ]
148           [    --stripes Number ]
149           [ COMMON_OPTIONS ]
150           [ PV ... ]
151       -
152
153       Convert LV to raid or change raid layout
154       (a specific raid level must be used, e.g. raid1).
155
156       lvconvert --type raid LV
157           [ -m|--mirrors [+|-]Number ]
158           [ -I|--stripesize Size[k|UNIT] ]
159           [ -R|--regionsize Size[m|UNIT] ]
160           [ -i|--interval Number ]
161           [    --stripes Number ]
162           [ COMMON_OPTIONS ]
163           [ PV ... ]
164       -
165
166       Convert LV to raid1 or mirror, or change number of mirror images.
167
168       lvconvert -m|--mirrors [+|-]Number LV
169           [ -R|--regionsize Size[m|UNIT] ]
170           [ -i|--interval Number ]
171           [    --mirrorlog core|disk ]
172           [ COMMON_OPTIONS ]
173           [ PV ... ]
174       -
175
176       Convert raid LV to change number of stripe images.
177
178       lvconvert --stripes Number LV_raid
179           [ -i|--interval Number ]
180           [ -R|--regionsize Size[m|UNIT] ]
181           [ -I|--stripesize Size[k|UNIT] ]
182           [ COMMON_OPTIONS ]
183           [ PV ... ]
184       -
185
186       Convert raid LV to change the stripe size.
187
188       lvconvert -I|--stripesize Size[k|UNIT] LV_raid
189           [ -i|--interval Number ]
190           [ -R|--regionsize Size[m|UNIT] ]
191           [ COMMON_OPTIONS ]
192       -
193
194       Split images from a raid1 or mirror LV and use them to create a new LV.
195
196       lvconvert --splitmirrors Number -n|--name LV_new LV_cache_mirror_raid1
197           [ COMMON_OPTIONS ]
198           [ PV ... ]
199       -
200
201       Split  images  from  a  raid1  LV and track changes to origin for later
202       merge.
203
204       lvconvert --splitmirrors Number --trackchanges LV_cache_raid1
205           [ COMMON_OPTIONS ]
206           [ PV ... ]
207       -
208
209       Merge LV images that were split from a raid1 LV.
210
211       lvconvert --mergemirrors VG|LV_linear_raid|Tag ...
212           [ COMMON_OPTIONS ]
213       -
214
215       Convert LV to a thin LV, using the original LV as an external origin.
216
217       lvconvert --type thin --thinpool LV LV_linear_striped_thin_cache_raid
218           [ -T|--thin ]
219           [ -r|--readahead auto|none|Number ]
220           [ -c|--chunksize Size[k|UNIT] ]
221           [ -Z|--zero y|n ]
222           [    --originname LV_new ]
223           [    --poolmetadata LV ]
224           [    --poolmetadatasize Size[m|UNIT] ]
225           [    --poolmetadataspare y|n ]
226           [    --metadataprofile String ]
227           [ COMMON_OPTIONS ]
228       -
229
230       Convert LV to type cache.
231
232       lvconvert --type cache --cachepool LV LV_linear_striped_thinpool_raid
233           [ -H|--cache ]
234           [ -Z|--zero y|n ]
235           [ -r|--readahead auto|none|Number ]
236           [ -c|--chunksize Size[k|UNIT] ]
237           [    --cachemetadataformat auto|1|2 ]
238           [    --cachemode writethrough|writeback|passthrough ]
239           [    --cachepolicy String ]
240           [    --cachesettings String ]
241           [    --poolmetadata LV ]
242           [    --poolmetadatasize Size[m|UNIT] ]
243           [    --poolmetadataspare y|n ]
244           [    --metadataprofile String ]
245           [ COMMON_OPTIONS ]
246       -
247
248       Convert LV to type thin-pool.
249
250       lvconvert --type thin-pool LV_linear_striped_cache_raid
251           [ -I|--stripesize Size[k|UNIT] ]
252           [ -r|--readahead auto|none|Number ]
253           [ -c|--chunksize Size[k|UNIT] ]
254           [ -Z|--zero y|n ]
255           [    --stripes Number ]
256           [    --discards passdown|nopassdown|ignore ]
257           [    --poolmetadata LV ]
258           [    --poolmetadatasize Size[m|UNIT] ]
259           [    --poolmetadataspare y|n ]
260           [    --metadataprofile String ]
261           [ COMMON_OPTIONS ]
262           [ PV ... ]
263       -
264
265       Convert LV to type cache-pool.
266
267       lvconvert --type cache-pool LV_linear_striped_raid
268           [ -Z|--zero y|n ]
269           [ -r|--readahead auto|none|Number ]
270           [ -c|--chunksize Size[k|UNIT] ]
271           [    --cachemetadataformat auto|1|2 ]
272           [    --cachemode writethrough|writeback|passthrough ]
273           [    --cachepolicy String ]
274           [    --cachesettings String ]
275           [    --poolmetadata LV ]
276           [    --poolmetadatasize Size[m|UNIT] ]
277           [    --poolmetadataspare y|n ]
278           [    --metadataprofile String ]
279           [ COMMON_OPTIONS ]
280           [ PV ... ]
281       -
282
283       Separate and keep the cache pool from a cache LV.
284
285       lvconvert --splitcache LV_thinpool_cache_cachepool
286           [ COMMON_OPTIONS ]
287       -
288
289       Merge thin LV into its origin LV.
290
291       lvconvert --mergethin LV_thin ...
292           [ COMMON_OPTIONS ]
293       -
294
295       Merge COW snapshot LV into its origin.
296
297       lvconvert --mergesnapshot LV_snapshot ...
298           [ -i|--interval Number ]
299           [ COMMON_OPTIONS ]
300       -
301
302       Combine a former COW snapshot (second arg) with a former
303       origin LV (first arg) to reverse a splitsnapshot command.
304
305       lvconvert --type snapshot LV LV_linear_striped
306           [ -s|--snapshot ]
307           [ -c|--chunksize Size[k|UNIT] ]
308           [ -Z|--zero y|n ]
309           [ COMMON_OPTIONS ]
310       -
311
312       Replace failed PVs in a raid or mirror LV.
313       Repair a thin pool.
314       Repair a cache pool.
315
316       lvconvert --repair LV_thinpool_cache_cachepool_mirror_raid
317           [ -i|--interval Number ]
318           [    --usepolicies ]
319           [    --poolmetadataspare y|n ]
320           [ COMMON_OPTIONS ]
321           [ PV ... ]
322       -
323
324       Replace specific PV(s) in a raid LV with another PV.
325
326       lvconvert --replace PV LV_raid
327           [ COMMON_OPTIONS ]
328           [ PV ... ]
329       -
330
331       Poll LV to continue conversion.
332
333       lvconvert --startpoll LV_mirror_raid
334           [ COMMON_OPTIONS ]
335       -
336
337       Common options for command:
338           [ -b|--background ]
339           [ -f|--force ]
340           [    --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
341           ]
342           [    --noudevsync ]
343
344       Common options for lvm:
345           [ -d|--debug ]
346           [ -h|--help ]
347           [ -q|--quiet ]
348           [ -t|--test ]
349           [ -v|--verbose ]
350           [ -y|--yes ]
351           [    --commandprofile String ]
352           [    --config String ]
353           [    --driverloaded y|n ]
354           [    --lockopt String ]
355           [    --longhelp ]
356           [    --profile String ]
357           [    --version ]
358

OPTIONS

360       --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
361              Determines the allocation policy when a command needs to allo‐
362              cate Physical Extents (PEs) from the VG. Each VG and LV has an
363              allocation policy which can be changed with vgchange/lvchange,
364              or overriden on the command line.  normal applies common sense
365              rules such as not placing parallel stripes on the same PV.
366              inherit applies the VG policy to an LV.  contiguous requires new
367              PEs be placed adjacent to existing PEs.  cling places new PEs on
368              the same PV as existing PEs in the same stripe of the LV.  If
369              there are sufficient PEs for an allocation, but normal does not
370              use them, anywhere will use them even if it reduces performance,
371              e.g. by placing two stripes on the same PV.  Optional positional
372              PV args on the command line can also be used to limit which PVs
373              the command will use for allocation.  See lvm(8) for more infor‐
374              mation about allocation.
375
376       -b|--background
377              If the operation requires polling, this option causes the com‐
378              mand to return before the operation is complete, and polling is
379              done in the background.
380
381       -H|--cache
382              Specifies the command is handling a cache LV or cache pool.  See
383              --type cache and --type cache-pool.  See lvmcache(7) for more
384              information about LVM caching.
385
386       --cachemetadataformat auto|1|2
387              Specifies the cache metadata format used by cache target.
388
389       --cachemode writethrough|writeback|passthrough
390              Specifies when writes to a cache LV should be considered com‐
391              plete.  writeback considers a write complete as soon as it is
392              stored in the cache pool.  writethough considers a write com‐
393              plete only when it has been stored in both the cache pool and on
394              the origin LV.  While writethrough may be slower for writes, it
395              is more resilient if something should happen to a device associ‐
396              ated with the cache pool LV. With passthrough, all reads are
397              served from the origin LV (all reads miss the cache) and all
398              writes are forwarded to the origin LV; additionally, write hits
399              cause cache block invalidates. See lvmcache(7) for more informa‐
400              tion.
401
402       --cachepolicy String
403              Specifies the cache policy for a cache LV.  See lvmcache(7) for
404              more information.
405
406       --cachepool LV
407              The name of a cache pool LV.
408
409       --cachesettings String
410              Specifies tunable values for a cache LV in "Key = Value" form.
411              Repeat this option to specify multiple values.  (The default
412              values should usually be adequate.)  The special string value
413              default switches settings back to their default kernel values
414              and removes them from the list of settings stored in LVM meta‐
415              data.  See lvmcache(7) for more information.
416
417       -c|--chunksize Size[k|UNIT]
418              The size of chunks in a snapshot, cache pool or thin pool.  For
419              snapshots, the value must be a power of 2 between 4KiB and
420              512KiB and the default value is 4.  For a cache pool the value
421              must be between 32KiB and 1GiB and the default value is 64.  For
422              a thin pool the value must be between 64KiB and 1GiB and the
423              default value starts with 64 and scales up to fit the pool meta‐
424              data size within 128MiB, if the pool metadata size is not speci‐
425              fied.  The value must be a multiple of 64KiB.  See lvmthin(7)
426              and lvmcache(7) for more information.
427
428       --commandprofile String
429              The command profile to use for command configuration.  See
430              lvm.conf(5) for more information about profiles.
431
432       --config String
433              Config settings for the command. These override lvm.conf set‐
434              tings.  The String arg uses the same format as lvm.conf, or may
435              use section/field syntax.  See lvm.conf(5) for more information
436              about config.
437
438       -d|--debug ...
439              Set debug level. Repeat from 1 to 6 times to increase the detail
440              of messages sent to the log file and/or syslog (if configured).
441
442       --discards passdown|nopassdown|ignore
443              Specifies how the device-mapper thin pool layer in the kernel
444              should handle discards.  ignore causes the thin pool to ignore
445              discards.  nopassdown causes the thin pool to process discards
446              itself to allow reuse of unneeded extents in the thin pool.
447              passdown causes the thin pool to process discards itself (like
448              nopassdown) and pass the discards to the underlying device.  See
449              lvmthin(7) for more information.
450
451       --driverloaded y|n
452              If set to no, the command will not attempt to use device-mapper.
453              For testing and debugging.
454
455       -f|--force ...
456              Override various checks, confirmations and protections.  Use
457              with extreme caution.
458
459       -h|--help
460              Display help text.
461
462       -i|--interval Number
463              Report progress at regular intervals.
464
465       --lockopt String
466              Used to pass options for special cases to lvmlockd.  See lvm‐
467              lockd(8) for more information.
468
469       --longhelp
470              Display long help text.
471
472       --merge
473              An alias for --mergethin, --mergemirrors, or --mergesnapshot,
474              depending on the type of LV.
475
476       --mergemirrors
477              Merge LV images that were split from a raid1 LV.  See --split‐
478              mirrors with --trackchanges.
479
480       --mergesnapshot
481              Merge COW snapshot LV into its origin.  When merging a snapshot,
482              if both the origin and snapshot LVs are not open, the merge will
483              start immediately. Otherwise, the merge will start the first
484              time either the origin or snapshot LV are activated and both are
485              closed. Merging a snapshot into an origin that cannot be closed,
486              for example a root filesystem, is deferred until the next time
487              the origin volume is activated. When merging starts, the result‐
488              ing LV will have the origin's name, minor number and UUID. While
489              the merge is in progress, reads or writes to the origin appear
490              as being directed to the snapshot being merged. When the merge
491              finishes, the merged snapshot is removed.  Multiple snapshots
492              may be specified on the command line or a @tag may be used to
493              specify multiple snapshots be merged to their respective origin.
494
495       --mergethin
496              Merge thin LV into its origin LV.  The origin thin LV takes the
497              content of the thin snapshot, and the thin snapshot LV is
498              removed.  See lvmthin(7) for more information.
499
500       --metadataprofile String
501              The metadata profile to use for command configuration.  See
502              lvm.conf(5) for more information about profiles.
503
504       --mirrorlog core|disk
505              Specifies the type of mirror log for LVs with the "mirror" type
506              (does not apply to the "raid1" type.)  disk is a persistent log
507              and requires a small amount of storage space, usually on a sepa‐
508              rate device from the data being mirrored.  core is not persis‐
509              tent; the log is kept only in memory.  In this case, the mirror
510              must be synchronized (by copying LV data from the first device
511              to others) each time the LV is activated, e.g. after reboot.
512              mirrored is a persistent log that is itself mirrored, but should
513              be avoided. Instead, use the raid1 type for log redundancy.
514
515       -m|--mirrors [+|-]Number
516              Specifies the number of mirror images in addition to the origi‐
517              nal LV image, e.g. --mirrors 1 means there are two images of the
518              data, the original and one mirror image.  Optional positional PV
519              args on the command line can specify the devices the images
520              should be placed on.  There are two mirroring implementations:
521              "raid1" and "mirror".  These are the names of the corresponding
522              LV types, or "segment types".  Use the --type option to specify
523              which to use (raid1 is default, and mirror is legacy) Use
524              lvm.conf global/mirror_segtype_default and global/raid10_seg‐
525              type_default to configure the default types.  The plus prefix +
526              can be used, in which case the number is added to the current
527              number of images, or the minus prefix - can be used, in which
528              case the number is subtracted from the current number of images.
529              See lvmraid(7) for more information.
530
531       -n|--name String
532              Specifies the name of a new LV.  When unspecified, a default
533              name of "lvol#" is generated, where # is a number generated by
534              LVM.
535
536       --noudevsync
537              Disables udev synchronisation. The process will not wait for
538              notification from udev. It will continue irrespective of any
539              possible udev processing in the background. Only use this if
540              udev is not running or has rules that ignore the devices LVM
541              creates.
542
543       --originname LV
544              Specifies the name to use for the external origin LV when con‐
545              verting an LV to a thin LV. The LV being converted becomes a
546              read-only external origin with this name.
547
548       --poolmetadata LV
549              The name of a an LV to use for storing pool metadata.
550
551       --poolmetadatasize Size[m|UNIT]
552              Specifies the size of the new pool metadata LV.
553
554       --poolmetadataspare y|n
555              Enable or disable the automatic creation and management of a
556              spare pool metadata LV in the VG. A spare metadata LV is
557              reserved space that can be used when repairing a pool.
558
559       --profile String
560              An alias for --commandprofile or --metadataprofile, depending on
561              the command.
562
563       -q|--quiet ...
564              Suppress output and log messages. Overrides --debug and --ver‐
565              bose.  Repeat once to also suppress any prompts with answer
566              'no'.
567
568       -r|--readahead auto|none|Number
569              Sets read ahead sector count of an LV.  auto is the default
570              which allows the kernel to choose a suitable value automati‐
571              cally.  none is equivalent to zero.
572
573       -R|--regionsize Size[m|UNIT]
574              Size of each raid or mirror synchronization region.  lvm.conf
575              activation/raid_region_size can be used to configure a default.
576
577       --repair
578              Replace failed PVs in a raid or mirror LV, or run a repair util‐
579              ity on a thin pool. See lvmraid(7) and lvmthin(7) for more
580              information.
581
582       --replace PV
583              Replace a specific PV in a raid LV with another PV.  The new PV
584              to use can be optionally specified after the LV.  Multiple PVs
585              can be replaced by repeating this option.  See lvmraid(7) for
586              more information.
587
588       -s|--snapshot
589              Combine a former COW snapshot LV with a former origin LV to
590              reverse a previous --splitsnapshot command.
591
592       --splitcache
593              Separates a cache pool from a cache LV, and keeps the unused
594              cache pool LV.  Before the separation, the cache is flushed.
595              Also see --uncache.
596
597       --splitmirrors Number
598              Splits the specified number of images from a raid1 or mirror LV
599              and uses them to create a new LV. If --trackchanges is also
600              specified, changes to the raid1 LV are tracked while the split
601              LV remains detached.  If --name is specified, then the images
602              are permanently split from the original LV and changes are not
603              tracked.
604
605       --splitsnapshot
606              Separates a COW snapshot from its origin LV. The LV that is
607              split off contains the chunks that differ from the origin LV
608              along with metadata describing them. This LV can be wiped and
609              then destroyed with lvremove.
610
611       --startpoll
612              Start polling an LV to continue processing a conversion.
613
614       --stripes Number
615              Specifies the number of stripes in a striped LV. This is the
616              number of PVs (devices) that a striped LV is spread across. Data
617              that appears sequential in the LV is spread across multiple
618              devices in units of the stripe size (see --stripesize). This
619              does not apply to existing allocated space, only newly allocated
620              space can be striped.
621
622       -I|--stripesize Size[k|UNIT]
623              The amount of data that is written to one device before moving
624              to the next in a striped LV.
625
626       --swapmetadata
627              Extracts the metadata LV from a pool and replaces it with
628              another specified LV.  The extracted LV is preserved and given
629              the name of the LV that replaced it.  Use for repair only. When
630              the metadata LV is swapped out of the pool, it can be activated
631              directly and used with thin provisioning tools: cache_dump(8),
632              cache_repair(8), cache_restore(8), thin_dump(8), thin_repair(8),
633              thin_restore(8).
634
635       -t|--test
636              Run in test mode. Commands will not update metadata.  This is
637              implemented by disabling all metadata writing but nevertheless
638              returning success to the calling function. This may lead to
639              unusual error messages in multi-stage operations if a tool
640              relies on reading back metadata it believes has changed but
641              hasn't.
642
643       -T|--thin
644              Specifies the command is handling a thin LV or thin pool.  See
645              --type thin, --type thin-pool, and --virtualsize.  See
646              lvmthin(7) for more information about LVM thin provisioning.
647
648       --thinpool LV
649              The name of a thin pool LV.
650
651       --trackchanges
652              Can be used with --splitmirrors on a raid1 LV. This causes
653              changes to the original raid1 LV to be tracked while the split
654              images remain detached. This is a temporary state that allows
655              the read-only detached image to be merged efficiently back into
656              the raid1 LV later.  Only the regions with changed data are
657              resynchronized during merge.  While a raid1 LV is tracking
658              changes, operations on it are limited to merging the split image
659              (see --mergemirrors) or permanently splitting the image (see
660              --splitmirrors with --name.
661
662       --type linear|striped|snapshot|mir‐
663              ror|raid|thin|cache|thin-pool|cache-pool
664              The LV type, also known as "segment type" or "segtype".  See
665              usage descriptions for the specific ways to use these types.
666              For more information about redundancy and performance (raid<N>,
667              mirror, striped, linear) see lvmraid(7).  For thin provisioning
668              (thin, thin-pool) see lvmthin(7).  For performance caching
669              (cache, cache-pool) see lvmcache(7).  For copy-on-write snap‐
670              shots (snapshot) see usage definitions.  Several commands omit
671              an explicit type option because the type is inferred from other
672              options or shortcuts (e.g. --stripes, --mirrors, --snapshot,
673              --virtualsize, --thin, --cache).  Use inferred types with care
674              because it can lead to unexpected results.
675
676       --uncache
677              Separates a cache pool from a cache LV, and deletes the unused
678              cache pool LV.  Before the separation, the cache is flushed.
679              Also see --splitcache.
680
681       --usepolicies
682              Perform an operation according to the policy configured in
683              lvm.conf or a profile.
684
685       -v|--verbose ...
686              Set verbose level. Repeat from 1 to 4 times to increase the
687              detail of messages sent to stdout and stderr.
688
689       --version
690              Display version information.
691
692       -y|--yes
693              Do not prompt for confirmation interactively but always assume
694              the answer yes. Use with extreme caution.  (For automatic no,
695              see -qq.)
696
697       -Z|--zero y|n
698              For snapshots, this controls zeroing of the first 4KiB of data
699              in the snapshot. If the LV is read-only, the snapshot will not
700              be zeroed.  For thin pools, this controls zeroing of provisioned
701              blocks.  Provisioning of large zeroed chunks negatively impacts
702              performance.
703

VARIABLES

705       VG
706              Volume Group name.  See lvm(8) for valid names.
707
708       LV
709              Logical Volume name.  See lvm(8) for valid names.  An  LV  posi‐
710              tional  arg  generally  includes  the  VG name and LV name, e.g.
711              VG/LV.  LV followed by _<type> indicates that an LV of the given
712              type is required. (raid represents raid<N> type)
713
714       PV
715              Physical  Volume  name,  a device path under /dev.  For commands
716              managing physical extents, a PV positional arg generally accepts
717              a  suffix  indicating  a  range (or multiple ranges) of physical
718              extents (PEs). When the first PE is omitted, it defaults to  the
719              start of the device, and when the last PE is omitted it defaults
720              to end.  Start and end range (inclusive):  PV[:PE-PE]...   Start
721              and length range (counting from 0): PV[:PE+PE]...
722
723       Tag
724              Tag  name.  See lvm(8) for information about tag names and using
725              tags in place of a VG, LV or PV.
726
727       String
728              See the option description for information about the string con‐
729              tent.
730
731       Size[UNIT]
732              Size  is  an  input number that accepts an optional unit.  Input
733              units are always treated as base two values, regardless of capi‐
734              talization,  e.g.  'k'  and 'K' both refer to 1024.  The default
735              input unit is specified by letter, followed by |UNIT.  UNIT rep‐
736              resents  other  possible  input units: bBsSkKmMgGtTpPeE.  b|B is
737              bytes, s|S is sectors of 512 bytes, k|K  is  kilobytes,  m|M  is
738              megabytes, g|G is gigabytes, t|T is terabytes, p|P is petabytes,
739              e|E is exabytes.  (This should not be confused with  the  output
740              control --units, where capital letters mean multiple of 1000.)
741

ENVIRONMENT VARIABLES

743       See  lvm(8)  for  information  about environment variables used by lvm.
744       For example, LVM_VG_NAME can generally be substituted for a required VG
745       parameter.
746

ADVANCED USAGE

748       Alternate  command  forms,  advanced  command usage, and listing of all
749       valid syntax for completeness.
750
751       Convert LV to type mirror (also see type raid1),
752       (also see lvconvert --mirrors).
753
754       lvconvert --type mirror LV
755           [ -m|--mirrors [+|-]Number ]
756           [ -R|--regionsize Size[m|UNIT] ]
757           [ -i|--interval Number ]
758           [    --mirrorlog core|disk ]
759           [ COMMON_OPTIONS ]
760           [ PV ... ]
761       -
762
763       Change the region size of an LV.
764
765       lvconvert -R|--regionsize Size[m|UNIT] LV_raid
766           [ COMMON_OPTIONS ]
767       -
768
769       Change the type of mirror log used by a mirror LV.
770
771       lvconvert --mirrorlog core|disk LV_mirror
772           [ COMMON_OPTIONS ]
773           [ PV ... ]
774       -
775
776       Convert LV to a thin LV, using the original LV as an external origin
777       (infers --type thin).
778
779       lvconvert -T|--thin --thinpool LV LV_linear_striped_thin_cache_raid
780           [ -r|--readahead auto|none|Number ]
781           [ -c|--chunksize Size[k|UNIT] ]
782           [ -Z|--zero y|n ]
783           [    --type thin ]
784           [    --originname LV_new ]
785           [    --poolmetadata LV ]
786           [    --poolmetadatasize Size[m|UNIT] ]
787           [    --poolmetadataspare y|n ]
788           [    --metadataprofile String ]
789           [ COMMON_OPTIONS ]
790       -
791
792       Convert LV to type cache (infers --type cache).
793
794       lvconvert -H|--cache --cachepool LV LV_linear_striped_thinpool_raid
795           [ -Z|--zero y|n ]
796           [ -r|--readahead auto|none|Number ]
797           [ -c|--chunksize Size[k|UNIT] ]
798           [    --type cache ]
799           [    --cachemetadataformat auto|1|2 ]
800           [    --cachemode writethrough|writeback|passthrough ]
801           [    --cachepolicy String ]
802           [    --cachesettings String ]
803           [    --poolmetadata LV ]
804           [    --poolmetadatasize Size[m|UNIT] ]
805           [    --poolmetadataspare y|n ]
806           [    --metadataprofile String ]
807           [ COMMON_OPTIONS ]
808       -
809
810       Separate and delete the cache pool from a cache LV.
811
812       lvconvert --uncache LV_thinpool_cache
813           [ COMMON_OPTIONS ]
814       -
815
816       Swap metadata LV in a thin pool or cache pool (for repair only).
817
818       lvconvert --swapmetadata --poolmetadata LV LV_thinpool_cachepool
819           [ -c|--chunksize Size[k|UNIT] ]
820           [ COMMON_OPTIONS ]
821       -
822
823       Merge LV that was split from a mirror (variant, use --mergemirrors).
824       Merge thin LV into its origin LV (variant, use --mergethin).
825       Merge COW snapshot LV into its origin (variant, use --mergesnapshot).
826
827       lvconvert --merge VG|LV_linear_striped_snapshot_thin_raid|Tag ...
828           [ -i|--interval Number ]
829           [ COMMON_OPTIONS ]
830       -
831
832       Separate a COW snapshot from its origin LV.
833
834       lvconvert --splitsnapshot LV_snapshot
835           [ COMMON_OPTIONS ]
836       -
837
838       Combine a former COW snapshot (second arg) with a former
839       origin LV (first arg) to reverse a splitsnapshot command.
840
841       lvconvert -s|--snapshot LV LV_linear_striped
842           [ -c|--chunksize Size[k|UNIT] ]
843           [ -Z|--zero y|n ]
844           [    --type snapshot ]
845           [ COMMON_OPTIONS ]
846       -
847
848       Poll LV to continue conversion (also see --startpoll)
849       or waits till conversion/mirror syncing is finished
850
851       lvconvert LV_mirror_raid
852           [ COMMON_OPTIONS ]
853       -
854
855

NOTES

857       This previous command syntax would perform two different operations:
858       lvconvert --thinpool LV1 --poolmetadata LV2
859       If LV1 was not a thin pool, the command would convert  LV1  to  a  thin
860       pool,  optionally  using  a specified LV for metadata.  But, if LV1 was
861       already a thin pool, the command would swap  the  current  metadata  LV
862       with LV2 (for repair purposes.)
863
864       In the same way, this previous command syntax would perform two differ‐
865       ent operations:
866       lvconvert --cachepool LV1 --poolmetadata LV2
867       If LV1 was not a cache pool, the command would convert LV1 to  a  cache
868       pool,  optionally  using  a specified LV for metadata.  But, if LV1 was
869       already a cache pool, the command would swap the  current  metadata  LV
870       with LV2 (for repair purposes.)
871

EXAMPLES

873       Convert a linear LV to a two-way mirror LV.
874       lvconvert --type mirror --mirrors 1 vg/lvol1
875
876       Convert a linear LV to a two-way RAID1 LV.
877       lvconvert --type raid1 --mirrors 1 vg/lvol1
878
879       Convert a mirror LV to use an in-memory log.
880       lvconvert --mirrorlog core vg/lvol1
881
882       Convert a mirror LV to use a disk log.
883       lvconvert --mirrorlog disk vg/lvol1
884
885       Convert a mirror or raid1 LV to a linear LV.
886       lvconvert --type linear vg/lvol1
887
888       Convert a mirror LV to a raid1 LV with the same number of images.
889       lvconvert --type raid1 vg/lvol1
890
891       Convert a linear LV to a two-way mirror LV, allocating new extents from
892       specific PV ranges.
893       lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15
894
895       Convert a mirror LV to a linear LV, freeing  physical  extents  from  a
896       specific PV.
897       lvconvert --type linear vg/lvol1 /dev/sda
898
899       Split one image from a mirror or raid1 LV, making it a new LV.
900       lvconvert --splitmirrors 1 --name lv_split vg/lvol1
901
902       Split one image from a raid1 LV, and track changes made to the raid1 LV
903       while the split image remains detached.
904       lvconvert --splitmirrors 1 --trackchanges vg/lvol1
905
906       Merge an image (that was previously  created  with  --splitmirrors  and
907       --trackchanges) back into the original raid1 LV.
908       lvconvert --mergemirrors vg/lvol1_rimage_1
909
910       Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV.
911       lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1
912
913       Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV.
914       lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1
915              vg/lvol1 /dev/sd[fgh]1
916
917       Replace  the  maximum  of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a
918       raid6 LV.
919       lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1
920
921       Convert an LV into a thin LV in the specified thin pool.  The  existing
922       LV is used as an external read-only origin for the new thin LV.
923       lvconvert --type thin --thinpool vg/tpool1 vg/lvol1
924
925       Convert  an LV into a thin LV in the specified thin pool.  The existing
926       LV is used as an external read-only origin for the new thin LV, and  is
927       renamed "external".
928       lvconvert --type thin --thinpool vg/tpool1
929              --originname external vg/lvol1
930
931       Convert  an  LV to a cache pool LV using another specified LV for cache
932       pool metadata.
933       lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1
934
935       Convert an LV to a cache LV using the specified cache  pool  and  chunk
936       size.
937       lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1
938
939       Detach and keep the cache pool from a cache LV.
940       lvconvert --splitcache vg/lvol1
941
942       Detach and remove the cache pool from a cache LV.
943       lvconvert --uncache vg/lvol1
944

SEE ALSO

946       lvm(8) lvm.conf(5) lvmconfig(8)
947
948       pvchange(8)  pvck(8)  pvcreate(8)  pvdisplay(8)  pvmove(8)  pvremove(8)
949       pvresize(8) pvs(8) pvscan(8)
950
951       vgcfgbackup(8) vgcfgrestore(8) vgchange(8) vgck(8)  vgcreate(8)  vgcon‐
952       vert(8)  vgdisplay(8)  vgexport(8)  vgextend(8)  vgimport(8)  vgimport‐
953       clone(8) vgmerge(8) vgmknodes(8)  vgreduce(8)  vgremove(8)  vgrename(8)
954       vgs(8) vgscan(8) vgsplit(8)
955
956       lvcreate(8)  lvchange(8)  lvconvert(8)  lvdisplay(8)  lvextend(8) lvre‐
957       duce(8) lvremove(8) lvrename(8) lvresize(8) lvs(8) lvscan(8)
958
959       lvm-fullreport(8) lvm-lvpoll(8) lvm2-activation-generator(8) blkdeacti‐
960       vate(8) lvmdump(8)
961
962       dmeventd(8)  lvmetad(8)  lvmpolld(8) lvmlockd(8) lvmlockctl(8) clvmd(8)
963       cmirrord(8) lvmdbusd(8)
964
965       lvmsystemid(7) lvmreport(7) lvmraid(7) lvmthin(7) lvmcache(7)
966
967
968
969Red Hat, Inc.         LVM TOOLS 2.02.183(2) (2018-12-07)          LVCONVERT(8)
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