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 --devices PV
31 --devicesfile String
32 --discards passdown|nopassdown|ignore
33 --driverloaded y|n
34 --errorwhenfull y|n
35 -f|--force
36 -h|--help
37 -i|--interval Number
38 --journal String
39 --lockopt String
40 --longhelp
41 --merge
42 --mergemirrors
43 --mergesnapshot
44 --mergethin
45 --metadataprofile String
46 --mirrorlog core|disk
47 -m|--mirrors [+|-]Number
48 -n|--name String
49 --nohints
50 --nolocking
51 --noudevsync
52 --originname LV
53 --poolmetadata LV
54 --poolmetadatasize Size[m|UNIT]
55 --poolmetadataspare y|n
56 --profile String
57 -q|--quiet
58 --raidintegrity y|n
59 --raidintegrityblocksize Number
60 --raidintegritymode String
61 -r|--readahead auto|none|Number
62 -R|--regionsize Size[m|UNIT]
63 --repair
64 --replace PV
65 -s|--snapshot
66 --splitcache
67 --splitmirrors Number
68 --splitsnapshot
69 --startpoll
70 --stripes Number
71 -I|--stripesize Size[k|UNIT]
72 --swapmetadata
73 -t|--test
74 -T|--thin
75 --thinpool LV
76 --trackchanges
77 --type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|
78 vdo-pool|cache|cache-pool|writecache
79 --uncache
80 --usepolicies
81 --vdopool LV
82 --vdosettings String
83 -v|--verbose
84 --version
85 -V|--virtualsize Size[m|UNIT]
86 -y|--yes
87 -Z|--zero y|n
88
90 lvconvert changes the LV type and includes utilities for LV data main‐
91 tenance. The LV type controls data layout and redundancy. The LV type
92 is also called the segment type or segtype.
93 To display the current LV type, run the command:
95 lvs -o name,segtype LV
97 In some cases, an LV is a single device mapper (dm) layer above physi‐
99 cal devices. In other cases, hidden LVs (dm devices) are layered be‐
100 tween the visible LV and physical devices. LVs in the middle layers
101 are called sub LVs. A command run on a visible LV sometimes operates
102 on a sub LV rather than the specified LV. In other cases, a sub LV
103 must be specified directly on the command line.
104 Sub LVs can be displayed with the command:
106 lvs -a
108 The linear type is equivalent to the striped type when one stripe ex‐
110 ists. In that case, the types can sometimes be used interchangably.
111 In most cases, the mirror type is deprecated and the raid1 type should
113 be used. They are both implementations of mirroring.
114 Striped raid types are raid0/raid0_meta, raid5 (an alias for raid5_ls),
116 raid6 (an alias for raid6_zr) and raid10 (an alias for raid10_near).
117 As opposed to mirroring, raid5 and raid6 stripe data and calculate par‐
119 ity blocks. The parity blocks can be used for data block recovery in
120 case devices fail. A maximum number of one device in a raid5 LV may
121 fail, and two in case of raid6. Striped raid types typically rotate the
122 parity and data blocks for performance reasons, thus avoiding con‐
123 tention on a single device. Specific arrangements of parity and data
124 blocks (layouts) can be used to optimize I/O performance, or to convert
125 between raid levels. See lvmraid(7) for more information.
126 Layouts of raid5 rotating parity blocks can be: left-asymmetric
128 (raid5_la), left-symmetric (raid5_ls with alias raid5), right-asymmet‐
129 ric (raid5_ra), right-symmetric (raid5_rs) and raid5_n, which doesn't
130 rotate parity blocks. Layouts of raid6 are: zero-restart (raid6_zr with
131 alias raid6), next-restart (raid6_nr), and next-continue (raid6_nc).
132 Layouts including _n allow for conversion between raid levels (raid5_n
134 to raid6 or raid5_n to striped/raid0/raid0_meta). Additionally, special
135 raid6 layouts for raid level conversions between raid5 and raid6 are:
136 raid6_ls_6, raid6_rs_6, raid6_la_6 and raid6_ra_6. Those correspond to
137 their raid5 counterparts (e.g. raid5_rs can be directly converted to
138 raid6_rs_6 and vice-versa).
139 raid10 (an alias for raid10_near) is currently limited to one data copy
141 and even number of sub LVs. This is a mirror group layout, thus a sin‐
142 gle sub LV may fail per mirror group without data loss.
143 Striped raid types support converting the layout, their stripesize and
145 their number of stripes.
146 The striped raid types combined with raid1 allow for conversion from
148 linear → striped/raid0/raid0_meta and vice-versa by e.g. linear ↔ raid1
149 ↔ raid5_n (then adding stripes) ↔ striped/raid0/raid0_meta.
150
152 Convert LV to linear.
153 lvconvert --type linear LV
155 [ COMMON_OPTIONS ]
156 [ PV ... ]
157 —
159 Convert LV to striped.
161 lvconvert --type striped LV
163 [ -I|--stripesize Size[k|UNIT] ]
164 [ -R|--regionsize Size[m|UNIT] ]
165 [ -i|--interval Number ]
166 [ --stripes Number ]
167 [ COMMON_OPTIONS ]
168 [ PV ... ]
169 —
171 Convert LV to type mirror (also see type raid1),
173 lvconvert --type mirror LV
175 [ -m|--mirrors [+|-]Number ]
176 [ -I|--stripesize Size[k|UNIT] ]
177 [ -R|--regionsize Size[m|UNIT] ]
178 [ -i|--interval Number ]
179 [ --stripes Number ]
180 [ --mirrorlog core|disk ]
181 [ COMMON_OPTIONS ]
182 [ PV ... ]
183 —
185 Convert LV to raid or change raid layout
187 (a specific raid level must be used, e.g. raid1).
188 lvconvert --type raid LV
190 [ -m|--mirrors [+|-]Number ]
191 [ -I|--stripesize Size[k|UNIT] ]
192 [ -R|--regionsize Size[m|UNIT] ]
193 [ -i|--interval Number ]
194 [ --stripes Number ]
195 [ COMMON_OPTIONS ]
196 [ PV ... ]
197 —
199 Convert LV to raid1 or mirror, or change number of mirror images.
201 lvconvert -m|--mirrors [+|-]Number LV
203 [ -R|--regionsize Size[m|UNIT] ]
204 [ -i|--interval Number ]
205 [ --mirrorlog core|disk ]
206 [ COMMON_OPTIONS ]
207 [ PV ... ]
208 —
210 Convert raid LV to change number of stripe images.
212 lvconvert --stripes Number LV1
214 [ -i|--interval Number ]
215 [ -R|--regionsize Size[m|UNIT] ]
216 [ -I|--stripesize Size[k|UNIT] ]
217 [ COMMON_OPTIONS ]
218 [ PV ... ]
219 LV1 types: raid
221 —
223 Convert raid LV to change the stripe size.
225 lvconvert -I|--stripesize Size[k|UNIT] LV1
227 [ -i|--interval Number ]
228 [ -R|--regionsize Size[m|UNIT] ]
229 [ COMMON_OPTIONS ]
230 LV1 types: raid
232 —
234 Split images from a raid1 or mirror LV and use them to create a new LV.
236 lvconvert --splitmirrors Number -n|--name LV_new LV1
238 [ COMMON_OPTIONS ]
239 [ PV ... ]
240 LV1 types: cache mirror raid1
242 —
244 Split images from a raid1 LV and track changes to origin for later
246 merge.
247 lvconvert --splitmirrors Number --trackchanges LV1
249 [ COMMON_OPTIONS ]
250 [ PV ... ]
251 LV1 types: cache raid1
253 —
255 Merge LV images that were split from a raid1 LV.
257 lvconvert --mergemirrors VG|LV1|Tag ...
259 [ COMMON_OPTIONS ]
260 LV1 types: linear raid
262 —
264 Convert LV to a thin LV, using the original LV as an external origin.
266 lvconvert --type thin --thinpool LV LV1
268 [ -T|--thin ]
269 [ -r|--readahead auto|none|Number ]
270 [ -c|--chunksize Size[k|UNIT] ]
271 [ -Z|--zero y|n ]
272 [ --originname LV_new ]
273 [ --poolmetadata LV ]
274 [ --poolmetadatasize Size[m|UNIT] ]
275 [ --poolmetadataspare y|n ]
276 [ --metadataprofile String ]
277 [ COMMON_OPTIONS ]
278 LV1 types: linear striped thin cache raid error zero
280 —
282 Attach a cache pool to an LV, converts the LV to type cache.
284 lvconvert --type cache --cachepool LV LV1
286 [ -H|--cache ]
287 [ -Z|--zero y|n ]
288 [ -r|--readahead auto|none|Number ]
289 [ -c|--chunksize Size[k|UNIT] ]
290 [ --cachemetadataformat auto|1|2 ]
291 [ --cachemode writethrough|writeback|passthrough ]
292 [ --cachepolicy String ]
293 [ --cachesettings String ]
294 [ --poolmetadata LV ]
295 [ --poolmetadatasize Size[m|UNIT] ]
296 [ --poolmetadataspare y|n ]
297 [ --metadataprofile String ]
298 [ COMMON_OPTIONS ]
299 LV1 types: linear striped thinpool vdo vdopool vdopooldata raid
301 —
303 Attach a writecache to an LV, converts the LV to type writecache.
305 lvconvert --type writecache --cachevol LV LV1
307 [ --cachesettings String ]
308 [ COMMON_OPTIONS ]
309 LV1 types: linear striped thinpool raid
311 —
313 Attach a cache to an LV, converts the LV to type cache.
315 lvconvert --type cache --cachevol LV LV1
317 [ -H|--cache ]
318 [ -Z|--zero y|n ]
319 [ -c|--chunksize Size[k|UNIT] ]
320 [ --cachemetadataformat auto|1|2 ]
321 [ --cachemode writethrough|writeback|passthrough ]
322 [ --cachepolicy String ]
323 [ --cachesettings String ]
324 [ --poolmetadatasize Size[m|UNIT] ]
325 [ COMMON_OPTIONS ]
326 LV1 types: linear striped thinpool raid
328 —
330 Add a writecache to an LV, using a specified cache device.
332 lvconvert --type writecache --cachedevice PV LV1
334 [ --cachesize Size[m|UNIT] ]
335 [ --cachesettings String ]
336 [ COMMON_OPTIONS ]
337 LV1 types: linear striped thinpool raid
339 —
341 Add a cache to an LV, using a specified cache device.
343 lvconvert --type cache --cachedevice PV LV1
345 [ -c|--chunksize Size[k|UNIT] ]
346 [ --cachesize Size[m|UNIT] ]
347 [ --cachesettings String ]
348 [ COMMON_OPTIONS ]
349 LV1 types: linear striped thinpool raid
351 —
353 Convert LV to type thin-pool.
355 lvconvert --type thin-pool LV1
357 [ -I|--stripesize Size[k|UNIT] ]
358 [ -r|--readahead auto|none|Number ]
359 [ -c|--chunksize Size[k|UNIT] ]
360 [ -Z|--zero y|n ]
361 [ --stripes Number ]
362 [ --discards passdown|nopassdown|ignore ]
363 [ --errorwhenfull y|n ]
364 [ --poolmetadata LV ]
365 [ --poolmetadatasize Size[m|UNIT] ]
366 [ --poolmetadataspare y|n ]
367 [ --metadataprofile String ]
368 [ COMMON_OPTIONS ]
369 [ PV ... ]
370 LV1 types: linear striped cache raid error zero writecache
372 —
374 Convert LV to type cache-pool.
376 lvconvert --type cache-pool LV1
378 [ -Z|--zero y|n ]
379 [ -r|--readahead auto|none|Number ]
380 [ -c|--chunksize Size[k|UNIT] ]
381 [ --cachemetadataformat auto|1|2 ]
382 [ --cachemode writethrough|writeback|passthrough ]
383 [ --cachepolicy String ]
384 [ --cachesettings String ]
385 [ --poolmetadata LV ]
386 [ --poolmetadatasize Size[m|UNIT] ]
387 [ --poolmetadataspare y|n ]
388 [ --metadataprofile String ]
389 [ COMMON_OPTIONS ]
390 [ PV ... ]
391 LV1 types: linear striped raid
393 —
395 Convert LV to type vdopool.
397 lvconvert --type vdo-pool LV1
399 [ -n|--name LV_new ]
400 [ -V|--virtualsize Size[m|UNIT] ]
401 [ -r|--readahead auto|none|Number ]
402 [ -Z|--zero y|n ]
403 [ --metadataprofile String ]
404 [ --compression y|n ]
405 [ --deduplication y|n ]
406 [ --vdosettings String ]
407 [ COMMON_OPTIONS ]
408 LV1 types: linear striped cache raid
410 —
412 Detach a cache from an LV.
414 lvconvert --splitcache LV1
416 [ --cachesettings String ]
417 [ COMMON_OPTIONS ]
418 LV1 types: thinpool cache cachepool vdopool writecache
420 —
422 Merge thin LV into its origin LV.
424 lvconvert --mergethin LV1 ...
426 [ COMMON_OPTIONS ]
427 LV1 types: thin
429 —
431 Merge COW snapshot LV into its origin.
433 lvconvert --mergesnapshot LV1 ...
435 [ -i|--interval Number ]
436 [ COMMON_OPTIONS ]
437 LV1 types: snapshot
439 —
441 Combine a former COW snapshot (second arg) with a former
443 origin LV (first arg) to reverse a splitsnapshot command.
444 lvconvert --type snapshot LV LV1
446 [ -s|--snapshot ]
447 [ -c|--chunksize Size[k|UNIT] ]
448 [ -Z|--zero y|n ]
449 [ COMMON_OPTIONS ]
450 LV1 types: linear striped
452 —
454 Replace failed PVs in a raid or mirror LV.
456 Repair a thin pool.
457 Repair a cache pool.
458 lvconvert --repair LV1
460 [ -i|--interval Number ]
461 [ --usepolicies ]
462 [ --poolmetadataspare y|n ]
463 [ COMMON_OPTIONS ]
464 [ PV ... ]
465 LV1 types: thinpool cache cachepool mirror raid
467 —
469 Replace specific PV(s) in a raid LV with another PV.
471 lvconvert --replace PV LV1
473 [ COMMON_OPTIONS ]
474 [ PV ... ]
475 LV1 types: raid
477 —
479 Poll LV to continue conversion.
481 lvconvert --startpoll LV1
483 [ COMMON_OPTIONS ]
484 LV1 types: mirror raid
486 —
488 Add or remove data integrity checksums to raid images.
490 lvconvert --raidintegrity y|n LV1
492 [ --raidintegritymode String ]
493 [ --raidintegrityblocksize Number ]
494 [ COMMON_OPTIONS ]
495 [ PV ... ]
496 LV1 types: raid
498 —
500 Common options for command:
502 [ -b|--background ]
503 [ -f|--force ]
504 [ --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
505 ]
506 [ --noudevsync ]
507 Common options for lvm:
509 [ -d|--debug ]
510 [ -h|--help ]
511 [ -q|--quiet ]
512 [ -t|--test ]
513 [ -v|--verbose ]
514 [ -y|--yes ]
515 [ --commandprofile String ]
516 [ --config String ]
517 [ --devices PV ]
518 [ --devicesfile String ]
519 [ --driverloaded y|n ]
520 [ --journal String ]
521 [ --lockopt String ]
522 [ --longhelp ]
523 [ --nohints ]
524 [ --nolocking ]
525 [ --profile String ]
526 [ --version ]
527
529 --alloc contiguous|cling|cling_by_tags|normal|anywhere|inherit
530 Determines the allocation policy when a command needs to allo‐
531 cate Physical Extents (PEs) from the VG. Each VG and LV has an
532 allocation policy which can be changed with vgchange/lvchange,
533 or overridden on the command line. normal applies common sense
534 rules such as not placing parallel stripes on the same PV. in‐
535 herit applies the VG policy to an LV. contiguous requires new
536 PEs be placed adjacent to existing PEs. cling places new PEs on
537 the same PV as existing PEs in the same stripe of the LV. If
538 there are sufficient PEs for an allocation, but normal does not
539 use them, anywhere will use them even if it reduces performance,
540 e.g. by placing two stripes on the same PV. Optional positional
541 PV args on the command line can also be used to limit which PVs
542 the command will use for allocation. See lvm(8) for more infor‐
543 mation about allocation.
544 -b|--background
546 If the operation requires polling, this option causes the com‐
547 mand to return before the operation is complete, and polling is
548 done in the background.
549 -H|--cache
551 Specifies the command is handling a cache LV or cache pool. See
552 --type cache and --type cache-pool. See lvmcache(7) for more
553 information about LVM caching.
554 --cachedevice PV
556 The name of a device to use for a cache.
557 --cachemetadataformat auto|1|2
559 Specifies the cache metadata format used by cache target.
560 --cachemode writethrough|writeback|passthrough
562 Specifies when writes to a cache LV should be considered com‐
563 plete. writeback considers a write complete as soon as it is
564 stored in the cache pool. writethough considers a write com‐
565 plete only when it has been stored in both the cache pool and on
566 the origin LV. While writethrough may be slower for writes, it
567 is more resilient if something should happen to a device associ‐
568 ated with the cache pool LV. With passthrough, all reads are
569 served from the origin LV (all reads miss the cache) and all
570 writes are forwarded to the origin LV; additionally, write hits
571 cause cache block invalidates. See lvmcache(7) for more informa‐
572 tion.
573 --cachepolicy String
575 Specifies the cache policy for a cache LV. See lvmcache(7) for
576 more information.
577 --cachepool LV
579 The name of a cache pool.
580 --cachesettings String
582 Specifies tunable kernel options for dm-cache or dm-writecache
583 LVs. Use the form 'option=value' or 'option1=value option2=val‐
584 ue', or repeat --cachesettings for each option being set. These
585 settings override the default kernel behaviors which are usually
586 adequate. To remove cachesettings and revert to the default ker‐
587 nel behaviors, use --cachesettings 'default' for dm-cache or an
588 empty string --cachesettings '' for dm-writecache. See lvm‐
589 cache(7) for more information.
590 --cachesize Size[m|UNIT]
592 The size of cache to use.
593 --cachevol LV
595 The name of a cache volume.
596 -c|--chunksize Size[k|UNIT]
598 The size of chunks in a snapshot, cache pool or thin pool. For
599 snapshots, the value must be a power of 2 between 4 KiB and
600 512 KiB and the default value is 4. For a cache pool the value
601 must be between 32 KiB and 1 GiB and the default value is 64.
602 For a thin pool the value must be between 64 KiB and 1 GiB and
603 the default value starts with 64 and scales up to fit the pool
604 metadata size within 128 MiB, if the pool metadata size is not
605 specified. The value must be a multiple of 64 KiB. See
606 lvmthin(7) and lvmcache(7) for more information.
607 --commandprofile String
609 The command profile to use for command configuration. See
610 lvm.conf(5) for more information about profiles.
611 --compression y|n
613 Controls whether compression is enabled or disable for VDO vol‐
614 ume. See lvmvdo(7) for more information about VDO usage.
615 --config String
617 Config settings for the command. These override lvm.conf(5) set‐
618 tings. The String arg uses the same format as lvm.conf(5), or
619 may use section/field syntax. See lvm.conf(5) for more informa‐
620 tion about config.
621 -d|--debug ...
623 Set debug level. Repeat from 1 to 6 times to increase the detail
624 of messages sent to the log file and/or syslog (if configured).
625 --deduplication y|n
627 Controls whether deduplication is enabled or disable for VDO
628 volume. See lvmvdo(7) for more information about VDO usage.
629 --devices PV
631 Restricts the devices that are visible and accessible to the
632 command. Devices not listed will appear to be missing. This op‐
633 tion can be repeated, or accepts a comma separated list of de‐
634 vices. This overrides the devices file.
635 --devicesfile String
637 A file listing devices that LVM should use. The file must exist
638 in /etc/lvm/devices/ and is managed with the lvmdevices(8) com‐
639 mand. This overrides the lvm.conf(5) devices/devicesfile and
640 devices/use_devicesfile settings.
641 --discards passdown|nopassdown|ignore
643 Specifies how the device-mapper thin pool layer in the kernel
644 should handle discards. ignore causes the thin pool to ignore
645 discards. nopassdown causes the thin pool to process discards
646 itself to allow reuse of unneeded extents in the thin pool.
647 passdown causes the thin pool to process discards itself (like
648 nopassdown) and pass the discards to the underlying device. See
649 lvmthin(7) for more information.
650 --driverloaded y|n
652 If set to no, the command will not attempt to use device-mapper.
653 For testing and debugging.
654 --errorwhenfull y|n
656 Specifies thin pool behavior when data space is exhausted. When
657 yes, device-mapper will immediately return an error when a thin
658 pool is full and an I/O request requires space. When no, de‐
659 vice-mapper will queue these I/O requests for a period of time
660 to allow the thin pool to be extended. Errors are returned if
661 no space is available after the timeout. (Also see dm-thin-pool
662 kernel module option no_space_timeout.) See lvmthin(7) for more
663 information.
664 -f|--force ...
666 Override various checks, confirmations and protections. Use
667 with extreme caution.
668 -h|--help
670 Display help text.
671 -i|--interval Number
673 Report progress at regular intervals.
674 --journal String
676 Record information in the systemd journal. This information is
677 in addition to information enabled by the lvm.conf log/journal
678 setting. command: record information about the command. out‐
679 put: record the default command output. debug: record full com‐
680 mand debugging.
681 --lockopt String
683 Used to pass options for special cases to lvmlockd. See lvm‐
684 lockd(8) for more information.
685 --longhelp
687 Display long help text.
688 --merge
690 An alias for --mergethin, --mergemirrors, or --mergesnapshot,
691 depending on the type of LV.
692 --mergemirrors
694 Merge LV images that were split from a raid1 LV. See --split‐
695 mirrors with --trackchanges.
696 --mergesnapshot
698 Merge COW snapshot LV into its origin. When merging a snapshot,
699 if both the origin and snapshot LVs are not open, the merge will
700 start immediately. Otherwise, the merge will start the first
701 time either the origin or snapshot LV are activated and both are
702 closed. Merging a snapshot into an origin that cannot be closed,
703 for example a root filesystem, is deferred until the next time
704 the origin volume is activated. When merging starts, the result‐
705 ing LV will have the origin's name, minor number and UUID. While
706 the merge is in progress, reads or writes to the origin appear
707 as being directed to the snapshot being merged. When the merge
708 finishes, the merged snapshot is removed. Multiple snapshots
709 may be specified on the command line or a @tag may be used to
710 specify multiple snapshots be merged to their respective origin.
711 --mergethin
713 Merge thin LV into its origin LV. The origin thin LV takes the
714 content of the thin snapshot, and the thin snapshot LV is re‐
715 moved. See lvmthin(7) for more information.
716 --metadataprofile String
718 The metadata profile to use for command configuration. See
719 lvm.conf(5) for more information about profiles.
720 --mirrorlog core|disk
722 Specifies the type of mirror log for LVs with the "mirror" type
723 (does not apply to the "raid1" type.) disk is a persistent log
724 and requires a small amount of storage space, usually on a sepa‐
725 rate device from the data being mirrored. core is not persis‐
726 tent; the log is kept only in memory. In this case, the mirror
727 must be synchronized (by copying LV data from the first device
728 to others) each time the LV is activated, e.g. after reboot.
729 mirrored is a persistent log that is itself mirrored, but should
730 be avoided. Instead, use the raid1 type for log redundancy.
731 -m|--mirrors [+|-]Number
733 Specifies the number of mirror images in addition to the origi‐
734 nal LV image, e.g. --mirrors 1 means there are two images of the
735 data, the original and one mirror image. Optional positional PV
736 args on the command line can specify the devices the images
737 should be placed on. There are two mirroring implementations:
738 "raid1" and "mirror". These are the names of the corresponding
739 LV types, or "segment types". Use the --type option to specify
740 which to use (raid1 is default, and mirror is legacy) Use
741 lvm.conf(5) global/mirror_segtype_default and global/raid10_seg‐
742 type_default to configure the default types. The plus prefix +
743 can be used, in which case the number is added to the current
744 number of images, or the minus prefix - can be used, in which
745 case the number is subtracted from the current number of images.
746 See lvmraid(7) for more information.
747 -n|--name String
749 Specifies the name of a new LV. When unspecified, a default
750 name of "lvol#" is generated, where # is a number generated by
751 LVM.
752 --nohints
754 Do not use the hints file to locate devices for PVs. A command
755 may read more devices to find PVs when hints are not used. The
756 command will still perform standard hint file invalidation where
757 appropriate.
758 --nolocking
760 Disable locking. Use with caution, concurrent commands may pro‐
761 duce incorrect results.
762 --noudevsync
764 Disables udev synchronisation. The process will not wait for no‐
765 tification from udev. It will continue irrespective of any pos‐
766 sible udev processing in the background. Only use this if udev
767 is not running or has rules that ignore the devices LVM creates.
768 --originname LV
770 Specifies the name to use for the external origin LV when con‐
771 verting an LV to a thin LV. The LV being converted becomes a
772 read-only external origin with this name.
773 --poolmetadata LV
775 The name of a an LV to use for storing pool metadata.
776 --poolmetadatasize Size[m|UNIT]
778 Specifies the size of the new pool metadata LV.
779 --poolmetadataspare y|n
781 Enable or disable the automatic creation and management of a
782 spare pool metadata LV in the VG. A spare metadata LV is re‐
783 served space that can be used when repairing a pool.
784 --profile String
786 An alias for --commandprofile or --metadataprofile, depending on
787 the command.
788 -q|--quiet ...
790 Suppress output and log messages. Overrides --debug and --ver‐
791 bose. Repeat once to also suppress any prompts with answer
792 'no'.
793 --raidintegrity y|n
795 Enable or disable data integrity checksums for raid images.
796 --raidintegrityblocksize Number
798 The block size to use for dm-integrity on raid images. The in‐
799 tegrity block size should usually match the device logical block
800 size, or the file system block size. It may be less than the
801 file system block size, but not less than the device logical
802 block size. Possible values: 512, 1024, 2048, 4096.
803 --raidintegritymode String
805 Use a journal (default) or bitmap for keeping integrity check‐
806 sums consistent in case of a crash. The bitmap areas are recal‐
807 culated after a crash, so corruption in those areas would not be
808 detected. A journal does not have this problem. The journal
809 mode doubles writes to storage, but can improve performance for
810 scattered writes packed into a single journal write. bitmap
811 mode can in theory achieve full write throughput of the device,
812 but would not benefit from the potential scattered write opti‐
813 mization.
814 -r|--readahead auto|none|Number
816 Sets read ahead sector count of an LV. auto is the default
817 which allows the kernel to choose a suitable value automatical‐
818 ly. none is equivalent to zero.
819 -R|--regionsize Size[m|UNIT]
821 Size of each raid or mirror synchronization region. lvm.conf(5)
822 activation/raid_region_size can be used to configure a default.
823 --repair
825 Replace failed PVs in a raid or mirror LV, or run a repair util‐
826 ity on a thin pool. See lvmraid(7) and lvmthin(7) for more in‐
827 formation.
828 --replace PV
830 Replace a specific PV in a raid LV with another PV. The new PV
831 to use can be optionally specified after the LV. Multiple PVs
832 can be replaced by repeating this option. See lvmraid(7) for
833 more information.
834 -s|--snapshot
836 Combine a former COW snapshot LV with a former origin LV to re‐
837 verse a previous --splitsnapshot command.
838 --splitcache
840 Separates a cache pool from a cache LV, and keeps the unused
841 cache pool LV. Before the separation, the cache is flushed. Al‐
842 so see --uncache.
843 --splitmirrors Number
845 Splits the specified number of images from a raid1 or mirror LV
846 and uses them to create a new LV. If --trackchanges is also
847 specified, changes to the raid1 LV are tracked while the split
848 LV remains detached. If --name is specified, then the images
849 are permanently split from the original LV and changes are not
850 tracked.
851 --splitsnapshot
853 Separates a COW snapshot from its origin LV. The LV that is
854 split off contains the chunks that differ from the origin LV
855 along with metadata describing them. This LV can be wiped and
856 then destroyed with lvremove.
857 --startpoll
859 Start polling an LV to continue processing a conversion.
860 --stripes Number
862 Specifies the number of stripes in a striped LV. This is the
863 number of PVs (devices) that a striped LV is spread across. Data
864 that appears sequential in the LV is spread across multiple de‐
865 vices in units of the stripe size (see --stripesize). This does
866 not apply to existing allocated space, only newly allocated
867 space can be striped.
868 -I|--stripesize Size[k|UNIT]
870 The amount of data that is written to one device before moving
871 to the next in a striped LV.
872 --swapmetadata
874 Extracts the metadata LV from a pool and replaces it with anoth‐
875 er specified LV. The extracted LV is preserved and given the
876 name of the LV that replaced it. Use for repair only. When the
877 metadata LV is swapped out of the pool, it can be activated di‐
878 rectly and used with thin provisioning tools: cache_dump(8),
879 cache_repair(8), cache_restore(8), thin_dump(8), thin_repair(8),
880 thin_restore(8).
881 -t|--test
883 Run in test mode. Commands will not update metadata. This is
884 implemented by disabling all metadata writing but nevertheless
885 returning success to the calling function. This may lead to un‐
886 usual error messages in multi-stage operations if a tool relies
887 on reading back metadata it believes has changed but hasn't.
888 -T|--thin
890 Specifies the command is handling a thin LV or thin pool. See
891 --type thin, --type thin-pool, and --virtualsize. See
892 lvmthin(7) for more information about LVM thin provisioning.
893 --thinpool LV
895 The name of a thin pool LV.
896 --trackchanges
898 Can be used with --splitmirrors on a raid1 LV. This causes
899 changes to the original raid1 LV to be tracked while the split
900 images remain detached. This is a temporary state that allows
901 the read-only detached image to be merged efficiently back into
902 the raid1 LV later. Only the regions with changed data are
903 resynchronized during merge. While a raid1 LV is tracking
904 changes, operations on it are limited to merging the split image
905 (see --mergemirrors) or permanently splitting the image (see
906 --splitmirrors with --name.
907 --type linear|striped|snapshot|raid|mirror|thin|thin-pool|vdo|vdo-pool|
909 cache|cache-pool|writecache
910 The LV type, also known as "segment type" or "segtype". See us‐
911 age descriptions for the specific ways to use these types. For
912 more information about redundancy and performance (raid<N>, mir‐
913 ror, striped, linear) see lvmraid(7). For thin provisioning
914 (thin, thin-pool) see lvmthin(7). For performance caching
915 (cache, cache-pool) see lvmcache(7). For copy-on-write snap‐
916 shots (snapshot) see usage definitions. For VDO (vdo) see lvmv‐
917 do(7). Several commands omit an explicit type option because
918 the type is inferred from other options or shortcuts (e.g.
919 --stripes, --mirrors, --snapshot, --virtualsize, --thin,
920 --cache, --vdo). Use inferred types with care because it can
921 lead to unexpected results.
922 --uncache
924 Separates a cache pool from a cache LV, and deletes the unused
925 cache pool LV. Before the separation, the cache is flushed. Al‐
926 so see --splitcache.
927 --usepolicies
929 Perform an operation according to the policy configured in
930 lvm.conf(5) or a profile.
931 --vdopool LV
933 The name of a VDO pool LV. See lvmvdo(7) for more information
934 about VDO usage.
935 --vdosettings String
937 Specifies tunable VDO options for VDO LVs. Use the form 'op‐
938 tion=value' or 'option1=value option2=value', or repeat
939 --vdosettings for each option being set. These settings over‐
940 ride the default VDO behaviors. To remove vdosettings and re‐
941 vert to the default VDO behaviors, use --vdosettings 'default'.
942 See lvmvdo(7) for more information.
943 -v|--verbose ...
945 Set verbose level. Repeat from 1 to 4 times to increase the de‐
946 tail of messages sent to stdout and stderr.
947 --version
949 Display version information.
950 -V|--virtualsize Size[m|UNIT]
952 The virtual size of a new thin LV. See lvmthin(7) for more in‐
953 formation about LVM thin provisioning. Using virtual size (-V)
954 and actual size (-L) together creates a sparse LV. lvm.conf(5)
955 global/sparse_segtype_default determines the default segment
956 type used to create a sparse LV. Anything written to a sparse
957 LV will be returned when reading from it. Reading from other
958 areas of the LV will return blocks of zeros. When using a snap‐
959 shot to create a sparse LV, a hidden virtual device is created
960 using the zero target, and the LV has the suffix _vorigin.
961 Snapshots are less efficient than thin provisioning when creat‐
962 ing large sparse LVs (GiB).
963 -y|--yes
965 Do not prompt for confirmation interactively but always assume
966 the answer yes. Use with extreme caution. (For automatic no,
967 see -qq.)
968 -Z|--zero y|n
970 For snapshots, this controls zeroing of the first 4 KiB of data
971 in the snapshot. If the LV is read-only, the snapshot will not
972 be zeroed. For thin pools, this controls zeroing of provisioned
973 blocks. Provisioning of large zeroed chunks negatively impacts
974 performance.
975
977 VG Volume Group name. See lvm(8) for valid names.
978 LV Logical Volume name. See lvm(8) for valid names. An LV posi‐
980 tional arg generally includes the VG name and LV name, e.g.
981 VG/LV. LV1 indicates the LV must have a specific type, where
982 the accepted LV types are listed. (raid represents raid<N>
983 type).
984 PV Physical Volume name, a device path under /dev. For commands
986 managing physical extents, a PV positional arg generally accepts
987 a suffix indicating a range (or multiple ranges) of physical ex‐
988 tents (PEs). When the first PE is omitted, it defaults to the
989 start of the device, and when the last PE is omitted it defaults
990 to end. Start and end range (inclusive): PV[:PE-PE]... Start
991 and length range (counting from 0): PV[:PE+PE]...
992 Tag Tag name. See lvm(8) for information about tag names and using
994 tags in place of a VG, LV or PV.
995 String See the option description for information about the string con‐
997 tent.
998 Size[UNIT]
1000 Size is an input number that accepts an optional unit. Input
1001 units are always treated as base two values, regardless of capi‐
1002 talization, e.g. 'k' and 'K' both refer to 1024. The default
1003 input unit is specified by letter, followed by |UNIT. UNIT rep‐
1004 resents other possible input units: b|B is bytes, s|S is sectors
1005 of 512 bytes, k|K is KiB, m|M is MiB, g|G is GiB, t|T is TiB,
1006 p|P is PiB, e|E is EiB. (This should not be confused with the
1007 output control --units, where capital letters mean multiple of
1008 1000.)
1009
1011 See lvm(8) for information about environment variables used by lvm.
1012 For example, LVM_VG_NAME can generally be substituted for a required VG
1013 parameter.
1014
1016 Alternate command forms, advanced command usage, and listing of all
1017 valid syntax for completeness.
1018 Change the region size of an LV.
1020 lvconvert -R|--regionsize Size[m|UNIT] LV1
1022 [ COMMON_OPTIONS ]
1023 LV1 types: raid
1025 —
1027 Change the type of mirror log used by a mirror LV.
1029 lvconvert --mirrorlog core|disk LV1
1031 [ COMMON_OPTIONS ]
1032 [ PV ... ]
1033 LV1 types: mirror
1035 —
1037 Convert LV to a thin LV, using the original LV as an external origin.
1039 lvconvert -T|--thin --thinpool LV LV1
1041 [ --type thin ] (implied)
1042 [ -r|--readahead auto|none|Number ]
1043 [ -c|--chunksize Size[k|UNIT] ]
1044 [ -Z|--zero y|n ]
1045 [ --originname LV_new ]
1046 [ --poolmetadata LV ]
1047 [ --poolmetadatasize Size[m|UNIT] ]
1048 [ --poolmetadataspare y|n ]
1049 [ --metadataprofile String ]
1050 [ COMMON_OPTIONS ]
1051 LV1 types: linear striped thin cache raid error zero
1053 —
1055 Attach a cache pool to an LV.
1057 lvconvert -H|--cache --cachepool LV LV1
1059 [ --type cache ] (implied)
1060 [ -Z|--zero y|n ]
1061 [ -r|--readahead auto|none|Number ]
1062 [ -c|--chunksize Size[k|UNIT] ]
1063 [ --cachemetadataformat auto|1|2 ]
1064 [ --cachemode writethrough|writeback|passthrough ]
1065 [ --cachepolicy String ]
1066 [ --cachesettings String ]
1067 [ --poolmetadata LV ]
1068 [ --poolmetadatasize Size[m|UNIT] ]
1069 [ --poolmetadataspare y|n ]
1070 [ --metadataprofile String ]
1071 [ COMMON_OPTIONS ]
1072 LV1 types: linear striped thinpool vdo vdopool vdopooldata raid
1074 —
1076 Attach a cache to an LV, converts the LV to type cache.
1078 lvconvert -H|--cache --cachevol LV LV1
1080 [ -Z|--zero y|n ]
1081 [ -c|--chunksize Size[k|UNIT] ]
1082 [ --cachemetadataformat auto|1|2 ]
1083 [ --cachemode writethrough|writeback|passthrough ]
1084 [ --cachepolicy String ]
1085 [ --cachesettings String ]
1086 [ --poolmetadatasize Size[m|UNIT] ]
1087 [ COMMON_OPTIONS ]
1088 LV1 types: linear striped thinpool raid
1090 —
1092 Convert LV to type vdopool.
1094 lvconvert --vdopool LV
1096 [ --type vdo-pool ] (implied)
1097 [ -r|--readahead auto|none|Number ]
1098 [ -Z|--zero y|n ]
1099 [ -n|--name LV_new ]
1100 [ -V|--virtualsize Size[m|UNIT] ]
1101 [ --metadataprofile String ]
1102 [ --compression y|n ]
1103 [ --deduplication y|n ]
1104 [ --vdosettings String ]
1105 [ COMMON_OPTIONS ]
1106 —
1108 Detach and delete a cache from an LV.
1110 lvconvert --uncache LV1
1112 [ --cachesettings String ]
1113 [ COMMON_OPTIONS ]
1114 LV1 types: thinpool cache vdopool writecache
1116 —
1118 Swap metadata LV in a thin pool or cache pool (for repair only).
1120 lvconvert --swapmetadata --poolmetadata LV LV1
1122 [ -c|--chunksize Size[k|UNIT] ]
1123 [ COMMON_OPTIONS ]
1124 LV1 types: thinpool cachepool
1126 —
1128 Merge LV that was split from a mirror (variant, use --mergemirrors).
1130 Merge thin LV into its origin LV (variant, use --mergethin).
1131 Merge COW snapshot LV into its origin (variant, use --mergesnapshot).
1132 lvconvert --merge VG|LV1|Tag ...
1134 [ -i|--interval Number ]
1135 [ COMMON_OPTIONS ]
1136 LV1 types: linear striped snapshot thin raid
1138 —
1140 Separate a COW snapshot from its origin LV.
1142 lvconvert --splitsnapshot LV1
1144 [ COMMON_OPTIONS ]
1145 LV1 types: snapshot
1147 —
1149 Combine a former COW snapshot (second arg) with a former
1151 origin LV (first arg) to reverse a splitsnapshot command.
1152 lvconvert -s|--snapshot LV LV1
1154 [ --type snapshot ] (implied)
1155 [ -c|--chunksize Size[k|UNIT] ]
1156 [ -Z|--zero y|n ]
1157 [ COMMON_OPTIONS ]
1158 LV1 types: linear striped
1160 —
1162 Poll LV to continue conversion (also see --startpoll)
1164 or waits till conversion/mirror syncing is finished
1165 lvconvert LV1
1167 [ COMMON_OPTIONS ]
1168 LV1 types: mirror raid
1170 —
1172
1174 This previous command syntax would perform two different operations:
1175 lvconvert --thinpool LV1 --poolmetadata LV2
1176 If LV1 was not a thin pool, the command would convert LV1 to a thin
1177 pool, optionally using a specified LV for metadata. But, if LV1 was
1178 already a thin pool, the command would swap the current metadata LV
1179 with LV2 (for repair purposes.)
1180 In the same way, this previous command syntax would perform two differ‐
1182 ent operations:
1183 lvconvert --cachepool LV1 --poolmetadata LV2
1184 If LV1 was not a cache pool, the command would convert LV1 to a cache
1185 pool, optionally using a specified LV for metadata. But, if LV1 was
1186 already a cache pool, the command would swap the current metadata LV
1187 with LV2 (for repair purposes.)
1188
1190 Convert a linear LV to a two-way mirror LV.
1191 lvconvert --type mirror --mirrors 1 vg/lvol1
1192 Convert a linear LV to a two-way RAID1 LV.
1194 lvconvert --type raid1 --mirrors 1 vg/lvol1
1195 Convert a mirror LV to use an in-memory log.
1197 lvconvert --mirrorlog core vg/lvol1
1198 Convert a mirror LV to use a disk log.
1200 lvconvert --mirrorlog disk vg/lvol1
1201 Convert a mirror or raid1 LV to a linear LV.
1203 lvconvert --type linear vg/lvol1
1204 Convert a mirror LV to a raid1 LV with the same number of images.
1206 lvconvert --type raid1 vg/lvol1
1207 Convert a linear LV to a two-way mirror LV, allocating new extents from
1209 specific PV ranges.
1210 lvconvert --mirrors 1 vg/lvol1 /dev/sda:0-15 /dev/sdb:0-15
1211 Convert a mirror LV to a linear LV, freeing physical extents from a
1213 specific PV.
1214 lvconvert --type linear vg/lvol1 /dev/sda
1215 Split one image from a mirror or raid1 LV, making it a new LV.
1217 lvconvert --splitmirrors 1 --name lv_split vg/lvol1
1218 Split one image from a raid1 LV, and track changes made to the raid1 LV
1220 while the split image remains detached.
1221 lvconvert --splitmirrors 1 --trackchanges vg/lvol1
1222 Merge an image (that was previously created with --splitmirrors and
1224 --trackchanges) back into the original raid1 LV.
1225 lvconvert --mergemirrors vg/lvol1_rimage_1
1226 Replace PV /dev/sdb1 with PV /dev/sdf1 in a raid1/4/5/6/10 LV.
1228 lvconvert --replace /dev/sdb1 vg/lvol1 /dev/sdf1
1229 Replace 3 PVs /dev/sd[b-d]1 with PVs /dev/sd[f-h]1 in a raid1 LV.
1231 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 --replace /dev/sdd1
1232 vg/lvol1 /dev/sd[fgh]1
1233 Replace the maximum of 2 PVs /dev/sd[bc]1 with PVs /dev/sd[gh]1 in a
1235 raid6 LV.
1236 lvconvert --replace /dev/sdb1 --replace /dev/sdc1 vg/lvol1 /dev/sd[gh]1
1237 Convert an LV into a thin LV in the specified thin pool. The existing
1239 LV is used as an external read-only origin for the new thin LV.
1240 lvconvert --type thin --thinpool vg/tpool1 vg/lvol1
1241 Convert an LV into a thin LV in the specified thin pool. The existing
1243 LV is used as an external read-only origin for the new thin LV, and is
1244 renamed "external".
1245 lvconvert --type thin --thinpool vg/tpool1
1246 --originname external vg/lvol1
1247 Convert an LV to a cache pool LV using another specified LV for cache
1249 pool metadata.
1250 lvconvert --type cache-pool --poolmetadata vg/poolmeta1 vg/lvol1
1251 Convert an LV to a cache LV using the specified cache pool and chunk
1253 size.
1254 lvconvert --type cache --cachepool vg/cpool1 -c 128 vg/lvol1
1255 Detach and keep the cache pool from a cache LV.
1257 lvconvert --splitcache vg/lvol1
1258 Detach and remove the cache pool from a cache LV.
1260 lvconvert --uncache vg/lvol1
1261
1263 lvm(8), lvm.conf(5), lvmconfig(8), lvmdevices(8),
1264 pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8),
1266 pvremove(8), pvresize(8), pvs(8), pvscan(8),
1267 vgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8), vgcreate(8),
1269 vgconvert(8), vgdisplay(8), vgexport(8), vgextend(8), vgimport(8),
1270 vgimportclone(8), vgimportdevices(8), vgmerge(8), vgmknodes(8),
1271 vgreduce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8), vgsplit(8),
1272 lvcreate(8), lvchange(8), lvconvert(8), lvdisplay(8), lvextend(8),
1274 lvreduce(8), lvremove(8), lvrename(8), lvresize(8), lvs(8), lvscan(8),
1275 lvm-fullreport(8), lvm-lvpoll(8), blkdeactivate(8), lvmdump(8),
1277 dmeventd(8), lvmpolld(8), lvmlockd(8), lvmlockctl(8), cmirrord(8),
1279 lvmdbusd(8), fsadm(8),
1280 lvmsystemid(7), lvmreport(7), lvmraid(7), lvmthin(7), lvmcache(7)
1282Red Hat, Inc. LVM TOOLS 2.03.18(2)-git (2022-11-10) LVCONVERT(8)