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The new option "--fs String" for lvresize/lvreduce/lvextend
controls the handling of file systems before/after resizing
the LV. --resizefs is the same as --fs resize.
The new option "--fsmode String" can be used to control
mounting and unmounting of the fs during resizing.
Possible --fs values:
checksize
Only applies to reducing size; does nothing for extend.
Check the fs size and reduce the LV if the fs is not using
the affected space, i.e. the fs does not need to be shrunk.
Fail the command without reducing the fs or LV if the fs is
using the affected space.
resize
Resize the fs using the fs-specific resize command.
This may include mounting, unmounting, or running fsck.
See --fsmode to control mounting behavior, and --nofsck to
disable fsck.
resize_fsadm
Use the old method of calling fsadm to handle the fs
(deprecated.) Warning: this option does not prevent lvreduce
from destroying file systems that are unmounted (or mounted
if prompts are skipped.)
ignore
Resize the LV without checking for or handling a file system.
Warning: using ignore when reducing the LV size may destroy the
file system.
Possible --fsmode values:
manage
Mount or unmount the fs as needed to resize the fs,
and attempt to restore the original mount state at the end.
nochange
Do not mount or unmount the fs. If mounting or unmounting
is required to resize the fs, then do not resize the fs or
the LV and fail the command.
offline
Unmount the fs if it is mounted, and resize the fs while it
is unmounted. If mounting is required to resize the fs,
then do not resize the fs or the LV and fail the command.
Notes on lvreduce:
When no --fs or --resizefs option is specified:
. lvextend default behavior is fs ignore.
. lvreduce default behavior is fs checksize
(includes activating the LV.)
With the exception of --fs resize_fsadm|ignore, lvreduce requires
the recent libblkid fields FSLASTBLOCK and FSBLOCKSIZE.
FSLASTBLOCK*FSBLOCKSIZE is the last byte used by the fs on the LV,
which determines if reducing the fs is necessary.
The new --valuesonly option causes the lvmconfig output to contain only
values without keys for each config node. This is practical mainly in
case where we use lvmconfig in scripts and we want to assign the value
to a different custom key or simply output the value itself without the
key.
For example:
# lvmconfig --type full activation/raid_fault_policy
raid_fault_policy="warn"
# lvmconfig --type full activation/raid_fault_policy --valuesonly
"warn"
# my_var=$(lvmconfig --type full activation/raid_fault_policy --valuesonly)
# echo $my_var
"warn"
Fixes commit b8f4ec846 "display: ignore --reportformat"
by restoring the --reportformat option to pvdisplay.
Adding -C to pvdisplay turns the command into a reporting
command (like pvs, vgs, lvs) in which --reportformat can
be useful.
Allow to use --vdosettings with lvcreate,lvconvert,lvchange.
Support settings currenly only configurable via lvm.conf.
With lvchange we require inactivate LV for changes to be applied.
Settings block_map_era_length has supported alias block_map_period.
Port the old pvscan -aay scanning optimization to vgchange -aay.
The optimization uses pvs_online files created by pvscan --cache
to derive a list of devices to use when activating a VG. This
allows autoactivation of a VG to avoid scanning all devices, and
only scan the devices used by the VG itself. The optimization is
applied internally using the device hints interface.
The new option "--autoactivation event" is given to pvscan and
vgchange commands that are called by event activation. This
informs the command that it is being used for event activation,
so that it can apply checks and optimizations that are specific
to event activation. Those include:
- skipping the command if lvm.conf event_activation=0
- checking that a VG is complete before activating it
- using pvs_online files to limit device scanning
Configure via lvm.conf log/journal or command line --journal.
Possible values:
"command" records command information.
"output" records default command output.
"debug" records full command debugging.
Multiple values can be set in lvm.conf as an array.
One value can be set in --journal which is added to
values set in lvm.conf
pvscan --cache <dev>
. read only dev
. create online file for dev
pvscan --listvg <dev>
. read only dev
. list VG using dev
pvscan --listlvs <dev>
. read only dev
. list VG using dev
. list LVs using dev
pvscan --cache --listvg [--checkcomplete] <dev>
. read only dev
. create online file for dev
. list VG using dev
. [check online files and report if VG is complete]
pvscan --cache --listlvs [--checkcomplete] <dev>
. read only dev
. create online file for dev
. list VG using dev
. list LVs using dev
. [check online files and report if VG is complete]
. [check online files and report if LVs are complete]
[--vgonline]
can be used with --checkcomplete, to enable use of a vg online
file. This results in only the first pvscan command to see
the complete VG to report 'VG complete', and others will report
'VG finished'. This allows the caller to easily run a single
activation of the VG.
[--udevoutput]
can be used with --cache --listvg --checkcomplete, to enable
an output mode that prints LVM_VG_NAME_COMPLETE='vgname' that
a udev rule can import, and prevents other output from the
command (other output causes udev to ignore the command.)
The list of complete LVs is meant to be passed to lvchange -aay,
or the complete VG used with vgchange -aay.
When --checkcomplete is used, lvm assumes that that the output
will be used to trigger event-based autoactivation, so the pvscan
does nothing if event_activation=0 and --checkcomplete is used.
Example of listlvs
------------------
$ lvs -a vg -olvname,devices
LV Devices
lv_a /dev/loop0(0)
lv_ab /dev/loop0(1),/dev/loop1(1)
lv_abc /dev/loop0(3),/dev/loop1(3),/dev/loop2(1)
lv_b /dev/loop1(0)
lv_c /dev/loop2(0)
$ pvscan --cache --listlvs --checkcomplete /dev/loop0
pvscan[35680] PV /dev/loop0 online, VG vg incomplete (need 2).
VG vg incomplete
LV vg/lv_a complete
LV vg/lv_ab incomplete
LV vg/lv_abc incomplete
$ pvscan --cache --listlvs --checkcomplete /dev/loop1
pvscan[35681] PV /dev/loop1 online, VG vg incomplete (need 1).
VG vg incomplete
LV vg/lv_b complete
LV vg/lv_ab complete
LV vg/lv_abc incomplete
$ pvscan --cache --listlvs --checkcomplete /dev/loop2
pvscan[35682] PV /dev/loop2 online, VG vg is complete.
VG vg complete
LV vg/lv_c complete
LV vg/lv_abc complete
Example of listvg
-----------------
$ pvscan --cache --listvg --checkcomplete /dev/loop0
pvscan[35684] PV /dev/loop0 online, VG vg incomplete (need 2).
VG vg incomplete
$ pvscan --cache --listvg --checkcomplete /dev/loop1
pvscan[35685] PV /dev/loop1 online, VG vg incomplete (need 1).
VG vg incomplete
$ pvscan --cache --listvg --checkcomplete /dev/loop2
pvscan[35686] PV /dev/loop2 online, VG vg is complete.
VG vg complete
When splitting VG with thin/cache pool volume, handle pmspare during
such split and allocate new pmspare in new VG or extend existing pmspare
there and eventually drop pmspare in original VG if is no longer needed
there.
When adding a device to the devices file with --adddev, lvm
by default chooses the best device ID type for the new device.
The new --deviceidtype option allows the user to override the
built in preference. This is useful if there's a problem with
the default type, or if a secondary type is preferrable.
If the specified deviceidtype does not produce a device ID,
then lvm falls back to the preference it would otherwise use.
If a cmd def implies an LV type without --type
in the required options, then include the implied
type in the cmd def as AUTOTYPE: <type>
instead of including the redundant --type foo
in the OO list of options.
Including an implied --type in the OO list would
often cause multiple cmd defs to potentially be
identical when options were used, and a user
command could match more than one cmd def.
The AUTOTYPE values are listed in man page and
help output as
[ --type foo (implied) ]
If a user command includes --type, it will usually
match a cmd def with --type in the required options.
But, if the user command matches a cmd def with
AUTOTYPE, then the specifed --type and AUTOTYPE must
match.
The man-generator program has a new --check
option that compares cmd defs to find any cmd defs
that are equivalent with the use of options,
and should have their options adjusted.
Add missing VG into description of thin pool creation command.
Remove one duplicated thin-pool creation command.
Remove options --discards and --errorwhenfull from the list when the command describes
only creation of a thin volume - as these options do apply for thin-pool.
Also use here more correct name OO_LVCONVERT_THINPOOL instead of OO_LVCONVERT_THIN.
Reorder extra options for cache & thin-pool before common pool options.
Order consistenly --stripes and --stripesize after --extents option
so the options related to pools are better together.
Remove invalid snapshot creation description - since this case is
handled through our configurable spare volume creation.
Add some missing optional --type parameters for few command instancies.
The autoactivation property can be specified in lvcreate
or vgcreate for new LVs/VGs, and the property can be changed
by lvchange or vgchange for existing LVs/VGs.
--setautoactivation y|n
enables|disables autoactivation of a VG or LV.
Autoactivation is enabled by default, which is consistent with
past behavior. The disabled state is stored as a new flag
in the VG metadata, and the absence of the flag allows
autoactivation.
If autoactivation is disabled for the VG, then no LVs in the VG
will be autoactivated (the LV autoactivation property will have
no effect.) When autoactivation is enabled for the VG, then
autoactivation can be controlled on individual LVs.
The state of this property can be reported for LVs/VGs using
the "-o autoactivation" option in lvs/vgs commands, which will
report "enabled", or "" for the disabled state.
Previous versions of lvm do not recognize this property. Since
autoactivation is enabled by default, the disabled setting will
have no effect in older lvm versions. If the VG is modified by
older lvm versions, the disabled state will also be dropped from
the metadata.
The autoactivation property is an alternative to using the lvm.conf
auto_activation_volume_list, which is still applied to to VGs/LVs
in addition to the new property.
If VG or LV autoactivation is disabled either in metadata or in
auto_activation_volume_list, it will not be autoactivated.
An autoactivation command will silently skip activating an LV
when the autoactivation property is disabled.
To determine the effective autoactivation behavior for a specific
LV, multiple settings would need to be checked:
the VG autoactivation property, the LV autoactivation property,
the auto_activation_volume_list. The "activation skip" property
would also be relevant, since it applies to both normal and auto
activation.
Renables usage of --type zero and --type error LVs to serve as
backend for _tdata device. Clearly not very useful in practice,
as it can't store any real data, but usable for some testing
and some sort of perfomance checking.
lvcreate --type zero -L1T -n pool vg
lvconvert --thinpool vg/pool
Will create a thin-pool with zero device backend.
The LVM devices file lists devices that lvm can use. The default
file is /etc/lvm/devices/system.devices, and the lvmdevices(8)
command is used to add or remove device entries. If the file
does not exist, or if lvm.conf includes use_devicesfile=0, then
lvm will not use a devices file. When the devices file is in use,
the regex filter is not used, and the filter settings in lvm.conf
or on the command line are ignored.
LVM records devices in the devices file using hardware-specific
IDs, such as the WWID, and attempts to use subsystem-specific
IDs for virtual device types. These device IDs are also written
in the VG metadata. When no hardware or virtual ID is available,
lvm falls back using the unstable device name as the device ID.
When devnames are used, lvm performs extra scanning to find
devices if their devname changes, e.g. after reboot.
When proper device IDs are used, an lvm command will not look
at devices outside the devices file, but when devnames are used
as a fallback, lvm will scan devices outside the devices file
to locate PVs on renamed devices. A config setting
search_for_devnames can be used to control the scanning for
renamed devname entries.
Related to the devices file, the new command option
--devices <devnames> allows a list of devices to be specified for
the command to use, overriding the devices file. The listed
devices act as a sort of devices file in terms of limiting which
devices lvm will see and use. Devices that are not listed will
appear to be missing to the lvm command.
Multiple devices files can be kept in /etc/lvm/devices, which
allows lvm to be used with different sets of devices, e.g.
system devices do not need to be exposed to a specific application,
and the application can use lvm on its own set of devices that are
not exposed to the system. The option --devicesfile <filename> is
used to select the devices file to use with the command. Without
the option set, the default system devices file is used.
Setting --devicesfile "" causes lvm to not use a devices file.
An existing, empty devices file means lvm will see no devices.
The new command vgimportdevices adds PVs from a VG to the devices
file and updates the VG metadata to include the device IDs.
vgimportdevices -a will import all VGs into the system devices file.
LVM commands run by dmeventd not use a devices file by default,
and will look at all devices on the system. A devices file can
be created for dmeventd (/etc/lvm/devices/dmeventd.devices) If
this file exists, lvm commands run by dmeventd will use it.
Internal implementaion:
- device_ids_read - read the devices file
. add struct dev_use (du) to cmd->use_devices for each devices file entry
- dev_cache_scan - get /dev entries
. add struct device (dev) to dev_cache for each device on the system
- device_ids_match - match devices file entries to /dev entries
. match each du on cmd->use_devices to a dev in dev_cache, using device ID
. on match, set du->dev, dev->id, dev->flags MATCHED_USE_ID
- label_scan - read lvm headers and metadata from devices
. filters are applied, those that do not need data from the device
. filter-deviceid skips devs without MATCHED_USE_ID, i.e.
skips /dev entries that are not listed in the devices file
. read lvm label from dev
. filters are applied, those that use data from the device
. read lvm metadata from dev
. add info/vginfo structs for PVs/VGs (info is "lvmcache")
- device_ids_find_renamed_devs - handle devices with unstable devname ID
where devname changed
. this step only needed when devs do not have proper device IDs,
and their dev names change, e.g. after reboot sdb becomes sdc.
. detect incorrect match because PVID in the devices file entry
does not match the PVID found when the device was read above
. undo incorrect match between du and dev above
. search system devices for new location of PVID
. update devices file with new devnames for PVIDs on renamed devices
. label_scan the renamed devs
- continue with command processing
User use 'lvconvert -Zn --type vdo-pool' to convert an existing
vdo formated volume and skip lvm2 internal formating.
This however requires user is passing proper matching parameters.
For them user can use --profile|--metadataprofile option whos
support has been also enhanced.
TODO: add support to read values directly from formated volume.
When converting an existing LV to thin-pool,
user may now pass also '--errorwhenfull' option
like with 'lvcreate'.
Also recalculate chunksize when performace profile is
used with conversion (again matching lvcreate).
Adds missing flagging for uncropped metadata sizes.
When detaching a writecache, use the cleaner setting
by default to writeback data prior to suspending the
lv to detach the writecache. This avoids potentially
blocking for a long period with the device suspended.
Detaching a writecache first sets the cleaner option, waits
for a short period of time (less than a second), and checks
if the writecache has quickly become clean. If so, the
writecache is detached immediately. This optimizes the case
where little writeback is needed.
If the writecache does not quickly become clean, then the
detach command leaves the writecache attached with the
cleaner option set. This leaves the LV in the same state
as if the user had set the cleaner option directly with
lvchange --cachesettings cleaner=1 LV.
After leaving the LV with the cleaner option set, the
detach command will wait and watch the writeback progress,
and will finally detach the writecache when the writeback
is finished. The detach command does not need to wait
during the writeback phase, and can be canceled, in which
case the LV will remain with the writecache attached and
the cleaner option set. When the user runs the detach
command again it will complete the detach.
To detach a writecache directly, without using the cleaner
step (which has been the approach previously), add the
option --cachesettings cleaner=0 to the detach command.
Allow the optional '--type raid1' to be included in the lvconvert
command when adding or removing raid images with integrity.
It does not change the meaning of the command (specifying a type
that matches the current type is redundant but generally allowed.)
To create a new cache or writecache LV with a single command:
lvcreate --type cache|writecache
-n Name -L Size --cachedevice PVfast VG [PVslow ...]
- A new main linear|striped LV is created as usual, using the
specified -n Name and -L Size, and using the optionally
specified PVslow devices.
- Then, a new cachevol LV is created internally, using PVfast
specified by the cachedevice option.
- Then, the cachevol is attached to the main LV, converting the
main LV to type cache|writecache.
Include --cachesize Size to specify the size of cache|writecache
to create from the specified --cachedevice PVs, otherwise the
entire cachedevice PV is used. The --cachedevice option can be
repeated to create the cache from multiple devices, or the
cachedevice option can contain a tag name specifying a set of PVs
to allocate the cache from.
To create a new cache or writecache LV with a single command
using an existing cachevol LV:
lvcreate --type cache|writecache
-n Name -L Size --cachevol LVfast VG [PVslow ...]
- A new main linear|striped LV is created as usual, using the
specified -n Name and -L Size, and using the optionally
specified PVslow devices.
- Then, the cachevol LVfast is attached to the main LV, converting
the main LV to type cache|writecache.
In cases where more advanced types (for the main LV or cachevol LV)
are needed, they should be created independently and then combined
with lvconvert.
Example
-------
user creates a new VG with one slow device and one fast device:
$ vgcreate vg /dev/slow1 /dev/fast1
user creates a new 8G main LV on /dev/slow1 that uses all of
/dev/fast1 as a writecache:
$ lvcreate --type writecache --cachedevice /dev/fast1
-n main -L 8G vg /dev/slow1
Example
-------
user creates a new VG with two slow devs and two fast devs:
$ vgcreate vg /dev/slow1 /dev/slow2 /dev/fast1 /dev/fast2
user creates a new 8G main LV on /dev/slow1 and /dev/slow2
that uses all of /dev/fast1 and /dev/fast2 as a writecache:
$ lvcreate --type writecache --cachedevice /dev/fast1 --cachedevice /dev/fast2
-n main -L 8G vg /dev/slow1 /dev/slow2
Example
-------
A user has several slow devices and several fast devices in their VG,
the slow devs have tag @slow, the fast devs have tag @fast.
user creates a new 8G main LV on the slow devs with a
2G writecache on the fast devs:
$ lvcreate --type writecache -n main -L 8G
--cachedevice @fast --cachesize 2G vg @slow
To add a cache or writecache to a main LV with a single command:
lvconvert --type cache|writecache --cachedevice /dev/ssd vg/main
A cachevol LV will be allocated from the specified cache device,
then attached to the main LV. Include --cachesize to specify the
size of cachevol to create, otherwise the entire cachedevice is
used. The cachedevice option can be repeated to create a cachevol
from multiple devices.
Example
-------
A user has an existing main LV that they want to speed up
using a new ssd.
user adds the new ssd to the VG:
$ vgextend vg /dev/ssd
user attaches the new ssd their main LV:
$ lvconvert --type writecache --cachedevice /dev/ssd vg/main
Example
-------
A user has two existing main LVs that they want to speed up
with a new ssd.
user adds the new 16G ssd to the VG:
$ vgextend vg /dev/ssd
user attaches some of the new ssd to the first main LV,
using half of the space:
$ lvconvert --type writecache --cachedevice /dev/ssd
--cachesize 8G vg/main1
user attaches some of the new ssd to the second main LV,
using the other half of the space:
$ lvconvert --type writecache --cachedevice /dev/ssd
--cachesize 8G vg/main2
Example
-------
A user has an existing main LV that they want to speed up using
two new ssds.
user adds the new two ssds the VG:
$ vgextend vg /dev/ssd1
$ vgextend vg /dev/ssd2
user attaches both ssds their main LV:
$ lvconvert --type writecache
--cachedevice /dev/ssd1 --cachedevice /dev/ssd2 vg/main
dm-integrity stores checksums of the data written to an
LV, and returns an error if data read from the LV does
not match the previously saved checksum. When used on
raid images, dm-raid will correct the error by reading
the block from another image, and the device user sees
no error. The integrity metadata (checksums) are stored
on an internal LV allocated by lvm for each linear image.
The internal LV is allocated on the same PV as the image.
Create a raid LV with an integrity layer over each
raid image (for raid levels 1,4,5,6,10):
lvcreate --type raidN --raidintegrity y [options]
Add an integrity layer to images of an existing raid LV:
lvconvert --raidintegrity y LV
Remove the integrity layer from images of a raid LV:
lvconvert --raidintegrity n LV
Settings
Use --raidintegritymode journal|bitmap (journal is default)
to configure the method used by dm-integrity to ensure
crash consistency.
Initialization
When integrity is added to an LV, the kernel needs to
initialize the integrity metadata/checksums for all blocks
in the LV. The data corruption checking performed by
dm-integrity will only operate on areas of the LV that
are already initialized. The progress of integrity
initialization is reported by the "syncpercent" LV
reporting field (and under the Cpy%Sync lvs column.)
Example: create a raid1 LV with integrity:
$ lvcreate --type raid1 -m1 --raidintegrity y -n rr -L1G foo
Creating integrity metadata LV rr_rimage_0_imeta with size 12.00 MiB.
Logical volume "rr_rimage_0_imeta" created.
Creating integrity metadata LV rr_rimage_1_imeta with size 12.00 MiB.
Logical volume "rr_rimage_1_imeta" created.
Logical volume "rr" created.
$ lvs -a foo
LV VG Attr LSize Origin Cpy%Sync
rr foo rwi-a-r--- 1.00g 4.93
[rr_rimage_0] foo gwi-aor--- 1.00g [rr_rimage_0_iorig] 41.02
[rr_rimage_0_imeta] foo ewi-ao---- 12.00m
[rr_rimage_0_iorig] foo -wi-ao---- 1.00g
[rr_rimage_1] foo gwi-aor--- 1.00g [rr_rimage_1_iorig] 39.45
[rr_rimage_1_imeta] foo ewi-ao---- 12.00m
[rr_rimage_1_iorig] foo -wi-ao---- 1.00g
[rr_rmeta_0] foo ewi-aor--- 4.00m
[rr_rmeta_1] foo ewi-aor--- 4.00m
To write a new/repaired pv_header and label_header:
pvck --repairtype pv_header --file <file> <device>
This uses the metadata input file to find the PV UUID,
device size, and data offset.
To write new/repaired metadata text and mda_header:
pvck --repairtype metadata --file <file> <device>
This requires a good pv_header which points to one or two
metadata areas. Any metadata areas referenced by the
pv_header are updated with the specified metadata and
a new mda_header. "--settings mda_num=1|2" can be used
to select one mda to repair.
To combine all header and metadata repairs:
pvck --repair --file <file> <device>
It's best to use a raw metadata file as input, that was
extracted from another PV in the same VG (or from another
metadata area on the same PV.) pvck will also accept a
metadata backup file, but that will produce metadata that
is not identical to other metadata copies on other PVs
and other areas. So, when using a backup file, consider
using it to update metadata on all PVs/areas.
To get a raw metadata file to use for the repair, see
pvck --dump metadata|metadata_search.
List all instances of metadata from the metadata area:
pvck --dump metadata_search <device>
Save one instance of metadata at the given offset to
the specified file (this file can be used for repair):
pvck --dump metadata_search --file <file>
--settings "metadata_offset=<off>" <device>
using --settings:
mda_offset=<offset> mda_size=<size> can be used
in place of the offset/size that normally come
from headers.
metadata_offset=<offset> prints/saves one instance
of metadata text at the given offset, in
metadata_all or metadata_search.
When pvscan is used to activate a VG via an
asynchronous service (i.e. lvm2-pvscan), there
is no requirement that the command wait for
udev to create device nodes before returning.
It's possible that waiting for udev is slow
enough to cause the service running the command
to time out. So, allow the --noudevsync option
to be given to pvscan to skip waiting for udev.
(This commit is not changing the lvm2-pvscan
service itself to use --noudevsync.)
Still unknown is whether there are any complex
LV activation cases in which lvm itself requires
access to a device node, in which case the udev
wait could be needed by lvm itself.
(When running an activation command directly
from the command line, it's generally expected
that the activated LVs are ready to use when
the command is finished, so lvm waits for
udev to finish creating the dev nodes.)
This allows the creation of a striped mirror leg(s) during upconvert
by adding lvconvert command line options --stripes/--stripesize
for 'mirror' to tools/command-lines.in.
In case multiple mirror legs are being added, all will have the
same requested striped layout.
Resolves: rhbz1720705
The -a was being included in the set of "one or more"
options instead of an actual required option. Even
though the cmd def was not implementing the restrictions
correctly, the command internally was.
Adjust the cmd def code which did not support a command
with some real required options and a set of "one or more"
options.
uses vg_write to correct more common or less severe issues,
and also adds the ability to repair some metadata corruption
that couldn't be handled previously.
Add 'pvck --dump headers' to print all the
lvm ondisk structs. Also checks the values
and prints any problems.
The previous dump metadata is also converted to
use these same routines, which do not depend on lvm
fully scanning/reading/processing the headers and
metadata on disk. This makes it useful to get data in
cases where there is corruption that would otherwise
prevent the normal functions from working.
The new command 'pvck --dump metadata PV' will extract
the current version of VG metadata from a PV for testing
and debugging. --dump metadata_area extracts the entire
text metadata area.
Allow using caching with VDO.
User can either cache a single vdopool or
a vdo LV - difference when the caching is put-in depends on a use-case
and it's upto user to decide which kind of speed is expected.
and "cachepool" to refer to a cache on a cache pool object.
The problem was that the --cachepool option was being used
to refer to both a cache pool object, and to a standard LV
used for caching. This could be somewhat confusing, and it
made it less clear when each kind would be used. By
separating them, it's clear when a cachepool or a cachevol
should be used.
Previously:
- lvm would use the cache pool approach when the user passed
a cache-pool LV to the --cachepool option.
- lvm would use the cache vol approach when the user passed
a standard LV in the --cachepool option.
Now:
- lvm will always use the cache pool approach when the user
uses the --cachepool option.
- lvm will always use the cache vol approach when the user
uses the --cachevol option.
Just like we support for thin-pool syntax:
lvcreate --thinpool new_tpoolname -L Size vg
add same support logic with for vdo-poo:
lvcreate --vdopool new_vpoolname -L Size vg
Also move description of syntax bellow thin-pool, so it's
correctly ordered in generated man page.
