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 --cachedevice PV
17 --cachemetadataformat auto|1|2
18 --cachemode writethrough|writeback|passthrough
19 --cachepolicy String
20 --cachepool LV
21 --cachesettings String
22 --cachesize Size[m|UNIT]
23 --cachevol LV
24 -c|--chunksize Size[k|UNIT]
25 --commandprofile String
26 --compression y|n
27 --config String
28 -d|--debug
29 --deduplication y|n
30 --discards passdown|nopassdown|ignore
31 --driverloaded y|n
32 -f|--force
33 -h|--help
34 -i|--interval Number
35 --lockopt String
36 --longhelp
37 --merge
38 --mergemirrors
39 --mergesnapshot
40 --mergethin
41 --metadataprofile String
42 --mirrorlog core|disk
43 -m|--mirrors [+|-]Number
44 -n|--name String
45 --nolocking
46 --noudevsync
47 --originname LV
48 --poolmetadata LV
49 --poolmetadatasize Size[m|UNIT]
50 --poolmetadataspare y|n
51 --profile String
52 -q|--quiet
53 --raidintegrity y|n
54 --raidintegrityblocksize Number
55 --raidintegritymode String
56 -r|--readahead auto|none|Number
57 -R|--regionsize Size[m|UNIT]
58 --repair
59 --replace PV
60 -s|--snapshot
61 --splitcache
62 --splitmirrors Number
63 --splitsnapshot
64 --startpoll
65 --stripes Number
66 -I|--stripesize Size[k|UNIT]
67 --swapmetadata
68 -t|--test
69 -T|--thin
70 --thinpool LV
71 --trackchanges
72 --type linear|striped|snapshot|mir‐
73 ror|raid|thin|cache|vdo|thin-pool|cache-pool|vdo-pool
74 --uncache
75 --usepolicies
76 --vdopool LV
77 -v|--verbose
78 --version
79 -V|--virtualsize Size[m|UNIT]
80 -y|--yes
81 -Z|--zero y|n
82
84 lvconvert changes the LV type and includes utilities for LV data main‐
85 tenance. The LV type controls data layout and redundancy. The LV type
86 is also called the segment type or segtype.
87 To display the current LV type, run the command:
89 lvs -o name,segtype LV
91 In some cases, an LV is a single device mapper (dm) layer above physi‐
93 cal devices. In other cases, hidden LVs (dm devices) are layered be‐
94 tween the visible LV and physical devices. LVs in the middle layers
95 are called sub LVs. A command run on a visible LV sometimes operates
96 on a sub LV rather than the specified LV. In other cases, a sub LV
97 must be specified directly on the command line.
98 Sub LVs can be displayed with the command:
100 lvs -a
102 The linear type is equivalent to the striped type when one stripe ex‐
104 ists. In that case, the types can sometimes be used interchangably.
105 In most cases, the mirror type is deprecated and the raid1 type should
107 be used. They are both implementations of mirroring.
108 Striped raid types are raid0/raid0_meta, raid5 (an alias for raid5_ls),
110 raid6 (an alias for raid6_zr) and raid10 (an alias for raid10_near).
111 As opposed to mirroring, raid5 and raid6 stripe data and calculate par‐
113 ity blocks. The parity blocks can be used for data block recovery in
114 case devices fail. A maximum number of one device in a raid5 LV may
115 fail, and two in case of raid6. Striped raid types typically rotate the
116 parity and data blocks for performance reasons, thus avoiding con‐
117 tention on a single device. Specific arrangements of parity and data
118 blocks (layouts) can be used to optimize I/O performance, or to convert
119 between raid levels. See lvmraid(7) for more information.
120 Layouts of raid5 rotating parity blocks can be: left-asymmetric
122 (raid5_la), left-symmetric (raid5_ls with alias raid5), right-asymmet‐
123 ric (raid5_ra), right-symmetric (raid5_rs) and raid5_n, which doesn't
124 rotate parity blocks. Layouts of raid6 are: zero-restart (raid6_zr with
125 alias raid6), next-restart (raid6_nr), and next-continue (raid6_nc).
126 Layouts including _n allow for conversion between raid levels (raid5_n
128 to raid6 or raid5_n to striped/raid0/raid0_meta). Additionally, special
129 raid6 layouts for raid level conversions between raid5 and raid6 are:
130 raid6_ls_6, raid6_rs_6, raid6_la_6 and raid6_ra_6. Those correspond to
131 their raid5 counterparts (e.g. raid5_rs can be directly converted to
132 raid6_rs_6 and vice-versa).
133 raid10 (an alias for raid10_near) is currently limited to one data copy
135 and even number of sub LVs. This is a mirror group layout, thus a sin‐
136 gle sub LV may fail per mirror group without data loss.
137 Striped raid types support converting the layout, their stripesize and
139 their number of stripes.
140 The striped raid types combined with raid1 allow for conversion from
142 linear-> striped/raid0/raid0_meta and vice-versa by e.g. linear <->
143 raid1 <-> raid5_n (then adding stripes) <-> striped/raid0/raid0_meta.
144
146 Convert LV to linear.
147 lvconvert --type linear LV
149 [ COMMON_OPTIONS ]
150 [ PV ... ]
151 -
152 Convert LV to striped.
154 lvconvert --type striped LV
156 [ -I|--stripesize Size[k|UNIT] ]
157 [ -R|--regionsize Size[m|UNIT] ]
158 [ -i|--interval Number ]
159 [ --stripes Number ]
160 [ COMMON_OPTIONS ]
161 [ PV ... ]
162 -
163 Convert LV to type mirror (also see type raid1),
165 lvconvert --type mirror LV
167 [ -m|--mirrors [+|-]Number ]
168 [ -I|--stripesize Size[k|UNIT] ]
169 [ -R|--regionsize Size[m|UNIT] ]
170 [ -i|--interval Number ]
171 [ --stripes Number ]
172 [ --mirrorlog core|disk ]
173 [ COMMON_OPTIONS ]
174 [ PV ... ]
175 -
176 Convert LV to raid or change raid layout
178 (a specific raid level must be used, e.g. raid1).
179 lvconvert --type raid LV
181 [ -m|--mirrors [+|-]Number ]
182 [ -I|--stripesize Size[k|UNIT] ]
183 [ -R|--regionsize Size[m|UNIT] ]
184 [ -i|--interval Number ]
185 [ --stripes Number ]
186 [ COMMON_OPTIONS ]
187 [ PV ... ]
188 -
189 Convert LV to raid1 or mirror, or change number of mirror images.
191 lvconvert -m|--mirrors [+|-]Number LV
193 [ -R|--regionsize Size[m|UNIT] ]
194 [ -i|--interval Number ]
195 [ --mirrorlog core|disk ]
196 [ COMMON_OPTIONS ]
197 [ PV ... ]
198 -
199 Convert raid LV to change number of stripe images.
201 lvconvert --stripes Number LV_raid
203 [ -i|--interval Number ]
204 [ -R|--regionsize Size[m|UNIT] ]
205 [ -I|--stripesize Size[k|UNIT] ]
206 [ COMMON_OPTIONS ]
207 [ PV ... ]
208 -
209 Convert raid LV to change the stripe size.
211 lvconvert -I|--stripesize Size[k|UNIT] LV_raid
213 [ -i|--interval Number ]
214 [ -R|--regionsize Size[m|UNIT] ]
215 [ COMMON_OPTIONS ]
216 -
217 Split images from a raid1 or mirror LV and use them to create a new LV.
219 lvconvert --splitmirrors Number -n|--name LV_new LV_cache_mirror_raid1
221 [ COMMON_OPTIONS ]
222 [ PV ... ]
223 -
224 Split images from a raid1 LV and track changes to origin for later
226 merge.
227 lvconvert --splitmirrors Number --trackchanges LV_cache_raid1
229 [ COMMON_OPTIONS ]
230 [ PV ... ]
231 -
232 Merge LV images that were split from a raid1 LV.
234 lvconvert --mergemirrors VG|LV_linear_raid|Tag ...
236 [ COMMON_OPTIONS ]
237 -
238 Convert LV to a thin LV, using the original LV as an external origin.
240 lvconvert --type thin --thinpool LV LV_linear_striped_thin_cache_raid
242 [ -T|--thin ]
243 [ -r|--readahead auto|none|Number ]
244 [ -c|--chunksize Size[k|UNIT] ]
245 [ -Z|--zero y|n ]
246 [ --originname LV_new ]
247 [ --poolmetadata LV ]
248 [ --poolmetadatasize Size[m|UNIT] ]
249 [ --poolmetadataspare y|n ]
250 [ --metadataprofile String ]
251 [ COMMON_OPTIONS ]
252 -
253 Attach a cache pool to an LV, converts the LV to type cache.
255 lvconvert --type cache --cachepool LV LV_linear_striped_thin‐
257 pool_vdo_vdopool_vdopooldata_raid
258 [ -H|--cache ]
259 [ -Z|--zero y|n ]
260 [ -r|--readahead auto|none|Number ]
261 [ -c|--chunksize Size[k|UNIT] ]
262 [ --cachemetadataformat auto|1|2 ]
263 [ --cachemode writethrough|writeback|passthrough ]
264 [ --cachepolicy String ]
265 [ --cachesettings String ]
266 [ --poolmetadata LV ]
267 [ --poolmetadatasize Size[m|UNIT] ]
268 [ --poolmetadataspare y|n ]
269 [ --metadataprofile String ]
270 [ COMMON_OPTIONS ]
271 -
272 Attach a writecache to an LV, converts the LV to type writecache.
274 lvconvert --type writecache --cachevol LV LV_linear_striped_raid
276 [ --cachesettings String ]
277 [ COMMON_OPTIONS ]
278 -
279 Attach a cache to an LV, converts the LV to type cache.
281 lvconvert --type cache --cachevol LV LV_linear_striped_thinpool_raid
283 [ -H|--cache ]
284 [ -Z|--zero y|n ]
285 [ -c|--chunksize Size[k|UNIT] ]
286 [ --cachemetadataformat auto|1|2 ]
287 [ --cachemode writethrough|writeback|passthrough ]
288 [ --cachepolicy String ]
289 [ --cachesettings String ]
290 [ --poolmetadatasize Size[m|UNIT] ]
291 [ COMMON_OPTIONS ]
292 -
293 Add a writecache to an LV, using a specified cache device.
295 lvconvert --type writecache --cachedevice PV LV_linear_striped_raid
297 [ --cachesize Size[m|UNIT] ]
298 [ --cachesettings String ]
299 [ COMMON_OPTIONS ]
300 -
301 Add a cache to an LV, using a specified cache device.
303 lvconvert --type cache --cachedevice PV LV_linear_striped_thinpool_raid
305 [ -c|--chunksize Size[k|UNIT] ]
306 [ --cachesize Size[m|UNIT] ]
307 [ --cachesettings String ]
308 [ COMMON_OPTIONS ]
309 -
310 Convert LV to type thin-pool.
312 lvconvert --type thin-pool LV_linear_striped_cache_raid
314 [ -I|--stripesize Size[k|UNIT] ]
315 [ -r|--readahead auto|none|Number ]
316 [ -c|--chunksize Size[k|UNIT] ]
317 [ -Z|--zero y|n ]
318 [ --stripes Number ]
319 [ --discards passdown|nopassdown|ignore ]
320 [ --poolmetadata LV ]
321 [ --poolmetadatasize Size[m|UNIT] ]
322 [ --poolmetadataspare y|n ]
323 [ --metadataprofile String ]
324 [ COMMON_OPTIONS ]
325 [ PV ... ]
326 -
327 Convert LV to type cache-pool.
329 lvconvert --type cache-pool LV_linear_striped_raid
331 [ -Z|--zero y|n ]
332 [ -r|--readahead auto|none|Number ]
333 [ -c|--chunksize Size[k|UNIT] ]
334 [ --cachemetadataformat auto|1|2 ]
335 [ --cachemode writethrough|writeback|passthrough ]
336 [ --cachepolicy String ]
337 [ --cachesettings String ]
338 [ --poolmetadata LV ]
339 [ --poolmetadatasize Size[m|UNIT] ]
340 [ --poolmetadataspare y|n ]
341 [ --metadataprofile String ]
342 [ COMMON_OPTIONS ]
343 [ PV ... ]
344 -
345 Convert LV to type vdopool.
347 lvconvert --type vdo-pool LV_linear_striped_cache_raid
349 [ -n|--name LV_new ]
350 [ -V|--virtualsize Size[m|UNIT] ]
351 [ --compression y|n ]
352 [ --deduplication y|n ]
353 [ COMMON_OPTIONS ]
354 -
355 Detach a cache from an LV.
357 lvconvert --splitcache LV_thinpool_cache_cachepool_vdopool_writecache
359 [ --cachesettings String ]
360 [ COMMON_OPTIONS ]
361 -
362 Merge thin LV into its origin LV.
364 lvconvert --mergethin LV_thin ...
366 [ COMMON_OPTIONS ]
367 -
368 Merge COW snapshot LV into its origin.
370 lvconvert --mergesnapshot LV_snapshot ...
372 [ -i|--interval Number ]
373 [ COMMON_OPTIONS ]
374 -
375 Combine a former COW snapshot (second arg) with a former
377 origin LV (first arg) to reverse a splitsnapshot command.
378 lvconvert --type snapshot LV LV_linear_striped
380 [ -s|--snapshot ]
381 [ -c|--chunksize Size[k|UNIT] ]
382 [ -Z|--zero y|n ]
383 [ COMMON_OPTIONS ]
384 -
385 Replace failed PVs in a raid or mirror LV.
387 Repair a thin pool.
388 Repair a cache pool.
389 lvconvert --repair LV_thinpool_cache_cachepool_mirror_raid
391 [ -i|--interval Number ]
392 [ --usepolicies ]
393 [ --poolmetadataspare y|n ]
394 [ COMMON_OPTIONS ]
395 [ PV ... ]
396 -
397 Replace specific PV(s) in a raid LV with another PV.
399 lvconvert --replace PV LV_raid
401 [ COMMON_OPTIONS ]
402 [ PV ... ]
403 -
404 Poll LV to continue conversion.
406 lvconvert --startpoll LV_mirror_raid
408 [ COMMON_OPTIONS ]
409 -
410 Add or remove data integrity checksums to raid images.
412 lvconvert --raidintegrity y|n LV_raid
414 [ --raidintegritymode String ]
415 [ --raidintegrityblocksize Number ]
416 [ COMMON_OPTIONS ]
417 [ PV ... ]
418 -
419 Common options for command:
421 [ -b|--background ]
422 [ -f|--force ]
423 [ --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
424 ]
425 [ --noudevsync ]
426 Common options for lvm:
428 [ -d|--debug ]
429 [ -h|--help ]
430 [ -q|--quiet ]
431 [ -t|--test ]
432 [ -v|--verbose ]
433 [ -y|--yes ]
434 [ --commandprofile String ]
435 [ --config String ]
436 [ --driverloaded y|n ]
437 [ --lockopt String ]
438 [ --longhelp ]
439 [ --nolocking ]
440 [ --profile String ]
441 [ --version ]
442
444 --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
445 Determines the allocation policy when a command needs to allo‐
446 cate Physical Extents (PEs) from the VG. Each VG and LV has an
447 allocation policy which can be changed with vgchange/lvchange,
448 or overriden on the command line. normal applies common sense
449 rules such as not placing parallel stripes on the same PV. in‐
450 herit applies the VG policy to an LV. contiguous requires new
451 PEs be placed adjacent to existing PEs. cling places new PEs on
452 the same PV as existing PEs in the same stripe of the LV. If
453 there are sufficient PEs for an allocation, but normal does not
454 use them, anywhere will use them even if it reduces performance,
455 e.g. by placing two stripes on the same PV. Optional positional
456 PV args on the command line can also be used to limit which PVs
457 the command will use for allocation. See lvm(8) for more infor‐
458 mation about allocation.
459 -b|--background
461 If the operation requires polling, this option causes the com‐
462 mand to return before the operation is complete, and polling is
463 done in the background.
464 -H|--cache
466 Specifies the command is handling a cache LV or cache pool. See
467 --type cache and --type cache-pool. See lvmcache(7) for more
468 information about LVM caching.
469 --cachedevice PV
471 The name of a device to use for a cache.
472 --cachemetadataformat auto|1|2
474 Specifies the cache metadata format used by cache target.
475 --cachemode writethrough|writeback|passthrough
477 Specifies when writes to a cache LV should be considered com‐
478 plete. writeback considers a write complete as soon as it is
479 stored in the cache pool. writethough considers a write com‐
480 plete only when it has been stored in both the cache pool and on
481 the origin LV. While writethrough may be slower for writes, it
482 is more resilient if something should happen to a device associ‐
483 ated with the cache pool LV. With passthrough, all reads are
484 served from the origin LV (all reads miss the cache) and all
485 writes are forwarded to the origin LV; additionally, write hits
486 cause cache block invalidates. See lvmcache(7) for more informa‐
487 tion.
488 --cachepolicy String
490 Specifies the cache policy for a cache LV. See lvmcache(7) for
491 more information.
492 --cachepool LV
494 The name of a cache pool.
495 --cachesettings String
497 Specifies tunable values for a cache LV in "Key = Value" form.
498 Repeat this option to specify multiple values. (The default
499 values should usually be adequate.) The special string value
500 default switches settings back to their default kernel values
501 and removes them from the list of settings stored in LVM meta‐
502 data. See lvmcache(7) for more information.
503 --cachesize Size[m|UNIT]
505 The size of cache to use.
506 --cachevol LV
508 The name of a cache volume.
509 -c|--chunksize Size[k|UNIT]
511 The size of chunks in a snapshot, cache pool or thin pool. For
512 snapshots, the value must be a power of 2 between 4KiB and
513 512KiB and the default value is 4. For a cache pool the value
514 must be between 32KiB and 1GiB and the default value is 64. For
515 a thin pool the value must be between 64KiB and 1GiB and the de‐
516 fault value starts with 64 and scales up to fit the pool meta‐
517 data size within 128MiB, if the pool metadata size is not speci‐
518 fied. The value must be a multiple of 64KiB. See lvmthin(7)
519 and lvmcache(7) for more information.
520 --commandprofile String
522 The command profile to use for command configuration. See
523 lvm.conf(5) for more information about profiles.
524 --compression y|n
526 Controls whether compression is enabled or disable for VDO vol‐
527 ume. See lvmvdo(7) for more information about VDO usage.
528 --config String
530 Config settings for the command. These override lvm.conf set‐
531 tings. The String arg uses the same format as lvm.conf, or may
532 use section/field syntax. See lvm.conf(5) for more information
533 about config.
534 -d|--debug ...
536 Set debug level. Repeat from 1 to 6 times to increase the detail
537 of messages sent to the log file and/or syslog (if configured).
538 --deduplication y|n
540 Controls whether deduplication is enabled or disable for VDO
541 volume. See lvmvdo(7) for more information about VDO usage.
542 --discards passdown|nopassdown|ignore
544 Specifies how the device-mapper thin pool layer in the kernel
545 should handle discards. ignore causes the thin pool to ignore
546 discards. nopassdown causes the thin pool to process discards
547 itself to allow reuse of unneeded extents in the thin pool.
548 passdown causes the thin pool to process discards itself (like
549 nopassdown) and pass the discards to the underlying device. See
550 lvmthin(7) for more information.
551 --driverloaded y|n
553 If set to no, the command will not attempt to use device-mapper.
554 For testing and debugging.
555 -f|--force ...
557 Override various checks, confirmations and protections. Use
558 with extreme caution.
559 -h|--help
561 Display help text.
562 -i|--interval Number
564 Report progress at regular intervals.
565 --lockopt String
567 Used to pass options for special cases to lvmlockd. See lvm‐
568 lockd(8) for more information.
569 --longhelp
571 Display long help text.
572 --merge
574 An alias for --mergethin, --mergemirrors, or --mergesnapshot,
575 depending on the type of LV.
576 --mergemirrors
578 Merge LV images that were split from a raid1 LV. See --split‐
579 mirrors with --trackchanges.
580 --mergesnapshot
582 Merge COW snapshot LV into its origin. When merging a snapshot,
583 if both the origin and snapshot LVs are not open, the merge will
584 start immediately. Otherwise, the merge will start the first
585 time either the origin or snapshot LV are activated and both are
586 closed. Merging a snapshot into an origin that cannot be closed,
587 for example a root filesystem, is deferred until the next time
588 the origin volume is activated. When merging starts, the result‐
589 ing LV will have the origin's name, minor number and UUID. While
590 the merge is in progress, reads or writes to the origin appear
591 as being directed to the snapshot being merged. When the merge
592 finishes, the merged snapshot is removed. Multiple snapshots
593 may be specified on the command line or a @tag may be used to
594 specify multiple snapshots be merged to their respective origin.
595 --mergethin
597 Merge thin LV into its origin LV. The origin thin LV takes the
598 content of the thin snapshot, and the thin snapshot LV is re‐
599 moved. See lvmthin(7) for more information.
600 --metadataprofile String
602 The metadata profile to use for command configuration. See
603 lvm.conf(5) for more information about profiles.
604 --mirrorlog core|disk
606 Specifies the type of mirror log for LVs with the "mirror" type
607 (does not apply to the "raid1" type.) disk is a persistent log
608 and requires a small amount of storage space, usually on a sepa‐
609 rate device from the data being mirrored. core is not persis‐
610 tent; the log is kept only in memory. In this case, the mirror
611 must be synchronized (by copying LV data from the first device
612 to others) each time the LV is activated, e.g. after reboot.
613 mirrored is a persistent log that is itself mirrored, but should
614 be avoided. Instead, use the raid1 type for log redundancy.
615 -m|--mirrors [+|-]Number
617 Specifies the number of mirror images in addition to the origi‐
618 nal LV image, e.g. --mirrors 1 means there are two images of the
619 data, the original and one mirror image. Optional positional PV
620 args on the command line can specify the devices the images
621 should be placed on. There are two mirroring implementations:
622 "raid1" and "mirror". These are the names of the corresponding
623 LV types, or "segment types". Use the --type option to specify
624 which to use (raid1 is default, and mirror is legacy) Use
625 lvm.conf global/mirror_segtype_default and global/raid10_seg‐
626 type_default to configure the default types. The plus prefix +
627 can be used, in which case the number is added to the current
628 number of images, or the minus prefix - can be used, in which
629 case the number is subtracted from the current number of images.
630 See lvmraid(7) for more information.
631 -n|--name String
633 Specifies the name of a new LV. When unspecified, a default
634 name of "lvol#" is generated, where # is a number generated by
635 LVM.
636 --nolocking
638 Disable locking.
639 --noudevsync
641 Disables udev synchronisation. The process will not wait for no‐
642 tification from udev. It will continue irrespective of any pos‐
643 sible udev processing in the background. Only use this if udev
644 is not running or has rules that ignore the devices LVM creates.
645 --originname LV
647 Specifies the name to use for the external origin LV when con‐
648 verting an LV to a thin LV. The LV being converted becomes a
649 read-only external origin with this name.
650 --poolmetadata LV
652 The name of a an LV to use for storing pool metadata.
653 --poolmetadatasize Size[m|UNIT]
655 Specifies the size of the new pool metadata LV.
656 --poolmetadataspare y|n
658 Enable or disable the automatic creation and management of a
659 spare pool metadata LV in the VG. A spare metadata LV is re‐
660 served space that can be used when repairing a pool.
661 --profile String
663 An alias for --commandprofile or --metadataprofile, depending on
664 the command.
665 -q|--quiet ...
667 Suppress output and log messages. Overrides --debug and --ver‐
668 bose. Repeat once to also suppress any prompts with answer
669 'no'.
670 --raidintegrity y|n
672 Enable or disable data integrity checksums for raid images.
673 --raidintegrityblocksize Number
675 The block size to use for dm-integrity on raid images. The in‐
676 tegrity block size should usually match the device logical block
677 size, or the file system block size. It may be less than the
678 file system block size, but not less than the device logical
679 block size. Possible values: 512, 1024, 2048, 4096.
680 --raidintegritymode String
682 Use a journal (default) or bitmap for keeping integrity check‐
683 sums consistent in case of a crash. The bitmap areas are recal‐
684 culated after a crash, so corruption in those areas would not be
685 detected. A journal does not have this problem. The journal
686 mode doubles writes to storage, but can improve performance for
687 scattered writes packed into a single journal write. bitmap
688 mode can in theory achieve full write throughput of the device,
689 but would not benefit from the potential scattered write opti‐
690 mization.
691 -r|--readahead auto|none|Number
693 Sets read ahead sector count of an LV. auto is the default
694 which allows the kernel to choose a suitable value automati‐
695 cally. none is equivalent to zero.
696 -R|--regionsize Size[m|UNIT]
698 Size of each raid or mirror synchronization region. lvm.conf
699 activation/raid_region_size can be used to configure a default.
700 --repair
702 Replace failed PVs in a raid or mirror LV, or run a repair util‐
703 ity on a thin pool. See lvmraid(7) and lvmthin(7) for more in‐
704 formation.
705 --replace PV
707 Replace a specific PV in a raid LV with another PV. The new PV
708 to use can be optionally specified after the LV. Multiple PVs
709 can be replaced by repeating this option. See lvmraid(7) for
710 more information.
711 -s|--snapshot
713 Combine a former COW snapshot LV with a former origin LV to re‐
714 verse a previous --splitsnapshot command.
715 --splitcache
717 Separates a cache pool from a cache LV, and keeps the unused
718 cache pool LV. Before the separation, the cache is flushed.
719 Also see --uncache.
720 --splitmirrors Number
722 Splits the specified number of images from a raid1 or mirror LV
723 and uses them to create a new LV. If --trackchanges is also
724 specified, changes to the raid1 LV are tracked while the split
725 LV remains detached. If --name is specified, then the images
726 are permanently split from the original LV and changes are not
727 tracked.
728 --splitsnapshot
730 Separates a COW snapshot from its origin LV. The LV that is
731 split off contains the chunks that differ from the origin LV
732 along with metadata describing them. This LV can be wiped and
733 then destroyed with lvremove.
734 --startpoll
736 Start polling an LV to continue processing a conversion.
737 --stripes Number
739 Specifies the number of stripes in a striped LV. This is the
740 number of PVs (devices) that a striped LV is spread across. Data
741 that appears sequential in the LV is spread across multiple de‐
742 vices in units of the stripe size (see --stripesize). This does
743 not apply to existing allocated space, only newly allocated
744 space can be striped.
745 -I|--stripesize Size[k|UNIT]
747 The amount of data that is written to one device before moving
748 to the next in a striped LV.
749 --swapmetadata
751 Extracts the metadata LV from a pool and replaces it with an‐
752 other specified LV. The extracted LV is preserved and given the
753 name of the LV that replaced it. Use for repair only. When the
754 metadata LV is swapped out of the pool, it can be activated di‐
755 rectly and used with thin provisioning tools: cache_dump(8),
756 cache_repair(8), cache_restore(8), thin_dump(8), thin_repair(8),
757 thin_restore(8).
758 -t|--test
760 Run in test mode. Commands will not update metadata. This is
761 implemented by disabling all metadata writing but nevertheless
762 returning success to the calling function. This may lead to un‐
763 usual error messages in multi-stage operations if a tool relies
764 on reading back metadata it believes has changed but hasn't.
765 -T|--thin
767 Specifies the command is handling a thin LV or thin pool. See
768 --type thin, --type thin-pool, and --virtualsize. See
769 lvmthin(7) for more information about LVM thin provisioning.
770 --thinpool LV
772 The name of a thin pool LV.
773 --trackchanges
775 Can be used with --splitmirrors on a raid1 LV. This causes
776 changes to the original raid1 LV to be tracked while the split
777 images remain detached. This is a temporary state that allows
778 the read-only detached image to be merged efficiently back into
779 the raid1 LV later. Only the regions with changed data are
780 resynchronized during merge. While a raid1 LV is tracking
781 changes, operations on it are limited to merging the split image
782 (see --mergemirrors) or permanently splitting the image (see
783 --splitmirrors with --name.
784 --type linear|striped|snapshot|mir‐
786 ror|raid|thin|cache|vdo|thin-pool|cache-pool|vdo-pool
787 The LV type, also known as "segment type" or "segtype". See us‐
788 age descriptions for the specific ways to use these types. For
789 more information about redundancy and performance (raid<N>, mir‐
790 ror, striped, linear) see lvmraid(7). For thin provisioning
791 (thin, thin-pool) see lvmthin(7). For performance caching
792 (cache, cache-pool) see lvmcache(7). For copy-on-write snap‐
793 shots (snapshot) see usage definitions. For VDO (vdo) see
794 lvmvdo(7). Several commands omit an explicit type option be‐
795 cause the type is inferred from other options or shortcuts (e.g.
796 --stripes, --mirrors, --snapshot, --virtualsize, --thin,
797 --cache, --vdo). Use inferred types with care because it can
798 lead to unexpected results.
799 --uncache
801 Separates a cache pool from a cache LV, and deletes the unused
802 cache pool LV. Before the separation, the cache is flushed.
803 Also see --splitcache.
804 --usepolicies
806 Perform an operation according to the policy configured in
807 lvm.conf or a profile.
808 --vdopool LV
810 The name of a VDO pool LV. See lvmvdo(7) for more information
811 about VDO usage.
812 -v|--verbose ...
814 Set verbose level. Repeat from 1 to 4 times to increase the de‐
815 tail of messages sent to stdout and stderr.
816 --version
818 Display version information.
819 -V|--virtualsize Size[m|UNIT]
821 The virtual size of a new thin LV. See lvmthin(7) for more in‐
822 formation about LVM thin provisioning. Using virtual size (-V)
823 and actual size (-L) together creates a sparse LV. lvm.conf
824 global/sparse_segtype_default determines the default segment
825 type used to create a sparse LV. Anything written to a sparse
826 LV will be returned when reading from it. Reading from other
827 areas of the LV will return blocks of zeros. When using a snap‐
828 shot to create a sparse LV, a hidden virtual device is created
829 using the zero target, and the LV has the suffix _vorigin.
830 Snapshots are less efficient than thin provisioning when creat‐
831 ing large sparse LVs (GiB).
832 -y|--yes
834 Do not prompt for confirmation interactively but always assume
835 the answer yes. Use with extreme caution. (For automatic no,
836 see -qq.)
837 -Z|--zero y|n
839 For snapshots, this controls zeroing of the first 4KiB of data
840 in the snapshot. If the LV is read-only, the snapshot will not
841 be zeroed. For thin pools, this controls zeroing of provisioned
842 blocks. Provisioning of large zeroed chunks negatively impacts
843 performance.
844
846 VG
847 Volume Group name. See lvm(8) for valid names.
848 LV
850 Logical Volume name. See lvm(8) for valid names. An LV posi‐
851 tional arg generally includes the VG name and LV name, e.g.
852 VG/LV. LV followed by _<type> indicates that an LV of the given
853 type is required. (raid represents raid<N> type)
854 PV
856 Physical Volume name, a device path under /dev. For commands
857 managing physical extents, a PV positional arg generally accepts
858 a suffix indicating a range (or multiple ranges) of physical ex‐
859 tents (PEs). When the first PE is omitted, it defaults to the
860 start of the device, and when the last PE is omitted it defaults
861 to end. Start and end range (inclusive): PV[:PE-PE]... Start
862 and length range (counting from 0): PV[:PE+PE]...
863 Tag
865 Tag name. See lvm(8) for information about tag names and using
866 tags in place of a VG, LV or PV.
867 String
869 See the option description for information about the string con‐
870 tent.
871 Size[UNIT]
873 Size is an input number that accepts an optional unit. Input
874 units are always treated as base two values, regardless of capi‐
875 talization, e.g. 'k' and 'K' both refer to 1024. The default
876 input unit is specified by letter, followed by |UNIT. UNIT rep‐
877 resents other possible input units: bBsSkKmMgGtTpPeE. b|B is
878 bytes, s|S is sectors of 512 bytes, k|K is KiB, m|M is MiB, g|G
879 is GiB, t|T is TiB, p|P is PiB, e|E is EiB. (This should not be
880 confused with the output control --units, where capital letters
881 mean multiple of 1000.)
882
884 See lvm(8) for information about environment variables used by lvm.
885 For example, LVM_VG_NAME can generally be substituted for a required VG
886 parameter.
887
889 Alternate command forms, advanced command usage, and listing of all
890 valid syntax for completeness.
891 Change the region size of an LV.
893 lvconvert -R|--regionsize Size[m|UNIT] LV_raid
895 [ COMMON_OPTIONS ]
896 -
897 Change the type of mirror log used by a mirror LV.
899 lvconvert --mirrorlog core|disk LV_mirror
901 [ COMMON_OPTIONS ]
902 [ PV ... ]
903 -
904 Convert LV to a thin LV, using the original LV as an external origin
906 (infers --type thin).
907 lvconvert -T|--thin --thinpool LV LV_linear_striped_thin_cache_raid
909 [ -r|--readahead auto|none|Number ]
910 [ -c|--chunksize Size[k|UNIT] ]
911 [ -Z|--zero y|n ]
912 [ --type thin ]
913 [ --originname LV_new ]
914 [ --poolmetadata LV ]
915 [ --poolmetadatasize Size[m|UNIT] ]
916 [ --poolmetadataspare y|n ]
917 [ --metadataprofile String ]
918 [ COMMON_OPTIONS ]
919 -
920 Attach a cache pool to an LV (infers --type cache).
922 lvconvert -H|--cache --cachepool LV LV_linear_striped_thin‐
924 pool_vdo_vdopool_vdopooldata_raid
925 [ -Z|--zero y|n ]
926 [ -r|--readahead auto|none|Number ]
927 [ -c|--chunksize Size[k|UNIT] ]
928 [ --type cache ]
929 [ --cachemetadataformat auto|1|2 ]
930 [ --cachemode writethrough|writeback|passthrough ]
931 [ --cachepolicy String ]
932 [ --cachesettings String ]
933 [ --poolmetadata LV ]
934 [ --poolmetadatasize Size[m|UNIT] ]
935 [ --poolmetadataspare y|n ]
936 [ --metadataprofile String ]
937 [ COMMON_OPTIONS ]
938 -
939 Attach a cache to an LV, converts the LV to type cache.
941 lvconvert -H|--cache --cachevol LV LV_linear_striped_thinpool_raid
943 [ -Z|--zero y|n ]
944 [ -c|--chunksize Size[k|UNIT] ]
945 [ --cachemetadataformat auto|1|2 ]
946 [ --cachemode writethrough|writeback|passthrough ]
947 [ --cachepolicy String ]
948 [ --cachesettings String ]
949 [ --poolmetadatasize Size[m|UNIT] ]
950 [ COMMON_OPTIONS ]
951 -
952 Convert LV to type vdopool.
954 lvconvert --vdopool LV_linear_striped_cache_raid
956 [ -n|--name LV_new ]
957 [ -V|--virtualsize Size[m|UNIT] ]
958 [ --type vdo-pool ]
959 [ --compression y|n ]
960 [ --deduplication y|n ]
961 [ COMMON_OPTIONS ]
962 -
963 Detach and delete a cache from an LV.
965 lvconvert --uncache LV_thinpool_cache_vdopool_writecache
967 [ --cachesettings String ]
968 [ COMMON_OPTIONS ]
969 -
970 Swap metadata LV in a thin pool or cache pool (for repair only).
972 lvconvert --swapmetadata --poolmetadata LV LV_thinpool_cachepool
974 [ -c|--chunksize Size[k|UNIT] ]
975 [ COMMON_OPTIONS ]
976 -
977 Merge LV that was split from a mirror (variant, use --mergemirrors).
979 Merge thin LV into its origin LV (variant, use --mergethin).
980 Merge COW snapshot LV into its origin (variant, use --mergesnapshot).
981 lvconvert --merge VG|LV_linear_striped_snapshot_thin_raid|Tag ...
983 [ -i|--interval Number ]
984 [ COMMON_OPTIONS ]
985 -
986 Separate a COW snapshot from its origin LV.
988 lvconvert --splitsnapshot LV_snapshot
990 [ COMMON_OPTIONS ]
991 -
992 Combine a former COW snapshot (second arg) with a former
994 origin LV (first arg) to reverse a splitsnapshot command.
995 lvconvert -s|--snapshot LV LV_linear_striped
997 [ -c|--chunksize Size[k|UNIT] ]
998 [ -Z|--zero y|n ]
999 [ --type snapshot ]
1000 [ COMMON_OPTIONS ]
1001 -
1002 Poll LV to continue conversion (also see --startpoll)
1004 or waits till conversion/mirror syncing is finished
1005 lvconvert LV_mirror_raid
1007 [ COMMON_OPTIONS ]
1008 -
1009
1012 This previous command syntax would perform two different operations:
1013 lvconvert --thinpool LV1 --poolmetadata LV2
1014 If LV1 was not a thin pool, the command would convert LV1 to a thin
1015 pool, optionally using a specified LV for metadata. But, if LV1 was
1016 already a thin pool, the command would swap the current metadata LV
1017 with LV2 (for repair purposes.)
1018 In the same way, this previous command syntax would perform two differ‐
1020 ent operations:
1021 lvconvert --cachepool LV1 --poolmetadata LV2
1022 If LV1 was not a cache pool, the command would convert LV1 to a cache
1023 pool, optionally using a specified LV for metadata. But, if LV1 was
1024 already a cache pool, the command would swap the current metadata LV
1025 with LV2 (for repair purposes.)
1026
1028 Convert a linear LV to a two-way mirror LV.
1029 lvconvert --type mirror --mirrors 1 vg/lvol1
1030 Convert a linear LV to a two-way RAID1 LV.
1032 lvconvert --type raid1 --mirrors 1 vg/lvol1
1033 Convert a mirror LV to use an in-memory log.
1035 lvconvert --mirrorlog core vg/lvol1
1036 Convert a mirror LV to use a disk log.
1038 lvconvert --mirrorlog disk vg/lvol1
1039 Convert a mirror or raid1 LV to a linear LV.
1041 lvconvert --type linear vg/lvol1
1042 Convert a mirror LV to a raid1 LV with the same number of images.
1044 lvconvert --type raid1 vg/lvol1
1045 Convert a linear LV to a two-way mirror LV, allocating new extents from
1047 specific PV ranges.
1048 lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15
1049 Convert a mirror LV to a linear LV, freeing physical extents from a
1051 specific PV.
1052 lvconvert --type linear vg/lvol1 /dev/sda
1053 Split one image from a mirror or raid1 LV, making it a new LV.
1055 lvconvert --splitmirrors 1 --name lv_split vg/lvol1
1056 Split one image from a raid1 LV, and track changes made to the raid1 LV
1058 while the split image remains detached.
1059 lvconvert --splitmirrors 1 --trackchanges vg/lvol1
1060 Merge an image (that was previously created with --splitmirrors and
1062 --trackchanges) back into the original raid1 LV.
1063 lvconvert --mergemirrors vg/lvol1_rimage_1
1064 Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV.
1066 lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1
1067 Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV.
1069 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1
1070 vg/lvol1 /dev/sd[fgh]1
1071 Replace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a
1073 raid6 LV.
1074 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1
1075 Convert an LV into a thin LV in the specified thin pool. The existing
1077 LV is used as an external read-only origin for the new thin LV.
1078 lvconvert --type thin --thinpool vg/tpool1 vg/lvol1
1079 Convert an LV into a thin LV in the specified thin pool. The existing
1081 LV is used as an external read-only origin for the new thin LV, and is
1082 renamed "external".
1083 lvconvert --type thin --thinpool vg/tpool1
1084 --originname external vg/lvol1
1085 Convert an LV to a cache pool LV using another specified LV for cache
1087 pool metadata.
1088 lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1
1089 Convert an LV to a cache LV using the specified cache pool and chunk
1091 size.
1092 lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1
1093 Detach and keep the cache pool from a cache LV.
1095 lvconvert --splitcache vg/lvol1
1096 Detach and remove the cache pool from a cache LV.
1098 lvconvert --uncache vg/lvol1
1099
1101 lvm(8) lvm.conf(5) lvmconfig(8)
1102 pvchange(8) pvck(8) pvcreate(8) pvdisplay(8) pvmove(8) pvremove(8)
1104 pvresize(8) pvs(8) pvscan(8)
1105 vgcfgbackup(8) vgcfgrestore(8) vgchange(8) vgck(8) vgcreate(8) vgcon‐
1107 vert(8) vgdisplay(8) vgexport(8) vgextend(8) vgimport(8) vgimport‐
1108 clone(8) vgmerge(8) vgmknodes(8) vgreduce(8) vgremove(8) vgrename(8)
1109 vgs(8) vgscan(8) vgsplit(8)
1110 lvcreate(8) lvchange(8) lvconvert(8) lvdisplay(8) lvextend(8) lvre‐
1112 duce(8) lvremove(8) lvrename(8) lvresize(8) lvs(8) lvscan(8)
1113 lvm-fullreport(8) lvm-lvpoll(8) lvm2-activation-generator(8) blkdeacti‐
1115 vate(8) lvmdump(8)
1116 dmeventd(8) lvmpolld(8) lvmlockd(8) lvmlockctl(8) cmirrord(8) lvmd‐
1118 busd(8)
1119 lvmsystemid(7) lvmreport(7) lvmraid(7) lvmthin(7) lvmcache(7)
1121Red Hat, Inc. LVM TOOLS 2.03.11(2) (2021-01-08) LVCONVERT(8)