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9a50df291a
Clean up and correct the details around --extents and --size. lvcreate/lvresize/lvreduce/lvextend all now display the extents option in usages. The Size and Number value variables for --size and --extents are now displayed without the [+|-] prefix for lvcreate.
40 lines
1.8 KiB
Plaintext
40 lines
1.8 KiB
Plaintext
lvcreate creates a new LV in a VG. For standard LVs, this requires
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allocating logical extents from the VG's free physical extents. If there
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is not enough free space, then the VG can be extended (see
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\fBvgextend\fP(8)) with other PVs, or existing LVs can be reduced or
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removed (see \fBlvremove\fP, \fBlvreduce\fP.)
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To control which PVs a new LV will use, specify one or more PVs as
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position args at the end of the command line. lvcreate will allocate
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physical extents only from the specified PVs.
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lvcreate can also create snapshots of existing LVs, e.g. for backup
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purposes. The data in a new snapshot LV represents the content of the
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original LV from the time the snapshot was created.
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RAID LVs can be created by specifying an LV type when creating the LV (see
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\fBlvmraid\fP(7)). Different RAID levels require different numbers of
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unique PVs be available in the VG for allocation.
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Thin pools (for thin provisioning) and cache pools (for caching) are
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represented by special LVs with types thin-pool and cache-pool (see
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\fBlvmthin\fP(7) and \fBlvmcache\fP(7)). The pool LVs are not usable as
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standard block devices, but the LV names act references to the pools.
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Thin LVs are thinly provisioned from a thin pool, and are created with a
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virtual size rather than a physical size. A cache LV is the combination of
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a standard LV with a cache pool, used to cache active portions of the LV
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to improve performance.
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.SS Usage notes
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In the usage section below, \fB--size\fP \fISize\fP can be replaced
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with \fB--extents\fP \fINumber\fP. See both descriptions
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the options section.
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In the usage section below, \fB--name\fP is omitted from the required
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options, even though it is typically used. When the name is not
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specified, a new LV name is generated with the "lvol" prefix and a unique
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numeric suffix. Also see the description in the options section.
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