lvcreate.1m (2010 09)

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lvcreate(1M) lvcreate(1M)

NAME

lvcreate - create a new logical volume or snapshot volume in LVM volume group

SYNOPSIS

Creating a Logical Volume

/usr/sbin/lvcreate

[-A autobackup ][-c mirror_consistency][

-C contiguous ][-d schedule ]

[

-D distributed ][-i stripes [

-I stripe_size ]] [-l le_number  -L lv_size ][-m mirror_copies]

[

-M mirror_write_cache][

-n lv_name ][

-p permission ][-r relocate ][-s strict ] vg_name

Creating a Snapshot Volume on Volume Group Version 2.2 or Higher

/usr/sbin/lvcreate -S

snap_type [-A autobackup ][

-c mirror_consistency][

-C contiguous ]

[

-D distributed ][-e auto_prealloc_enabled][

-l prealloc_le_number |

-L prealloc_le_size][

-m

mirror_copies ][-M mirror_write_cache][

-n snap_lv_name ][-p permission ][-P

threshold_value][

-s strict ][-t timestamp ]

original_lv

Remarks

Mirrored disk operations require the installation of the optional HP MirrorDisk/UX software, which is not

included in the standard HP-UX operating system.

DESCRIPTION

The

lvcreate command can be used in two ways. The ﬁrst form creates a new logical volume within

the volume group speciﬁed by vg_name. The second form, used with the -S

option, creates a snapshot

volume off an existing logical volume; see Creating Snapshot Volumes below.

The total number of logical volumes that can be created depends on the version of the volume group. Use

the

lvmadm command to ﬁnd the maximum number of logical volumes for each volume group version.

See lvm(7) for more information.

If you specify the

-n lv_name option, a new logical volume is created with that given name. Otherwise, a

system-generated name of the form

lvolN is created. For a logical volume created within a volume

group version 1.0, N is the decimal equivalent of the two least signiﬁcant bytes of the minor number of

the new logical volume and the range for N is 1 to 255. For a logical volume created within a volume

group version 2.0, N is the decimal equivalent of the least signiﬁcant 12 bits of the logical volumes minor

number, and the range for N is 1 to 511. For a logical volume created within a volume group version 2.1

and 2.2, N is the decimal equivalent of the least signiﬁcant 12 bits of the logical volumes minor number,

and the range for N is 1 to 2047 (see lvm (7)).

Two device ﬁles are created in vg_name : a block device ﬁle named lv_name or

lvolN, and a character

(raw) device ﬁle named

rlv_name or rlvolN.

If you omit the

-l and -L options, the logical volume is created with zero length. This permits you to

choose its physical volume location when you allocate logical extents with the lvextend command (see

lvextend (1M)). If you specify -l or -L, the location is determined automatically.

The default settings provide the most commonly used characteristics. Use the options to tailor the logical

volume to the requirements of the system. Once a logical volume is created, some of its characteristics

can be changed with the

lvchange, lvextend, and lvreduce commands (see lvchange (1M),

lvextend (1M), and lvreduce (1M)).

Creating Snapshot Volumes

The second form of

lvcreate uses the -S option to create a snapshot volume of an existing logical

volume within a volume group. Snapshots can be of two types: fully-allocated and space-efﬁcient. See

lvm(7) for more information about snapshots.

The snapshot volume is created as just another logical volume in the volume group. The following condi-

tions apply to the creation of snapshot volumes:

• It is necessary to provide an original logical volume.

• The allocation policies of the snapshot are inherited from the original logical volume unless speciﬁed

explicitly, with the exception that contiguous allocation policy is not supported for space-efﬁcient

snapshots. The allocation policy of a space-efﬁcient snapshot is set to default allocation when the ori-

ginal logical volume is conﬁgured for contiguous allocation.

• The snapshot is striped only if the original logical volume is striped. Specifying the stripe size or

stripe width for snapshots is not supported.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (10 pages)

PAGE 1
lvcreate(1M) lvcreate(1M) NAME lvcreate - create a new logical volume or snapshot volume in LVM volume group SYNOPSIS Creating a Logical Volume /usr/sbin/lvcreate [-A autobackup ] [-c mirror_consistency] [-C contiguous ] [-d schedule ] [-D distributed ] [-i stripes [-I stripe_size ]] [-l le_number  -L lv_size ] [-m mirror_copies] [-M mirror_write_cache] [-n lv_name ] [-p permission ] [-r relocate ] [-s strict ] vg_name Creating a Snapshot Volume on Volume Group Version 2.
PAGE 2
lvcreate(1M) lvcreate(1M) • A snapshot defaults to non-mirrored even if the original logical volume is mirrored, unless mirroring is explicitly configured during the snapshot creation. • When mirrored, a snapshot defaults to inherit the original logical volume’s MCR/MWC configuration, unless MCR/MWC is explicately configured during snapshot configuration.
PAGE 3
lvcreate(1M) -S snap_type lvcreate(1M) Create a point-in-time image of data. Current valid snap_type is: s Indicates the creation of a snapshot volume. See lvm(7) for more information on snapshot volume. If the -S option is not used, lvcreate creates a new logical volume instead of a snapshot off an existing logical volume. -A autobackup Set automatic backup for this invocation of this command.
PAGE 4
lvcreate(1M) -D distributed lvcreate(1M) Set the distributed allocation policy. distributed can have one of the following values: y Turn on distributed allocation. n Turn off distributed allocation. This is the default. When the distributed allocation policy is turned on, only one free extent is allocated from the first available physical volume. The next free extent is allocated from the next available physical volume.
PAGE 5
lvcreate(1M) -l lvcreate(1M) Allocate space, specified in logical extents, to the logical volume or snapshot volume. -l le_number allocates space to the logical volume, specified in logical extents. le_number must be at least 1 and no greater than a volume group version-dependent maximum; use the lvmadm command to determine the maximum number of logical extents for the volume group version. -l prealloc_le_number allocates space for a space-efficient snapshot volume.
PAGE 6
lvcreate(1M) lvcreate(1M) n -n Set Mirror Write Cache to off. Mirror write does not incur an additional write to the Mirror Consistency Record. Specify the name of the new logical volume or snapshot volume. -n lv_name sets the name of the new logical volume to lv_name , where lv_name is a simple file name, not a path name. -n snap_lv_name sets the name of the new snapshot volume to snap_lv_name .
PAGE 7
lvcreate(1M) lvcreate(1M) not have a physical volume group defined. n -t timestamp Do not set a strict or PVG-strict allocation policy. Mirrors of a logical extent can share the same physical volume. Append a timestamp to the snapshot volume name, in the form: YYYYMMDD_HH.MM.SS. timestamp can be one of the following: y Append the timestamp to the snapshot volume name. n Do not append the timestamp to the snapshot volume name. This is the default.
PAGE 8
lvcreate(1M) lvcreate(1M) lvcreate /dev/vg02 Create a logical volume in volume group /dev/vg03 with non-strict allocation policy: lvcreate -s n /dev/vg03 Create a logical volume of size 100 MB in volume group /dev/vg03: lvcreate -L 100 /dev/vg03 Create a space-efficient snapshot of size 10MB of the original logical volume /dev/vg03/lvol1: lvcreate -S s -L 10 /dev/vg03/lvol1 Create a space-efficient snapshot of size 10MB of the original logical volume /dev/vg03/lvol1 with the threshold value set to 50%:
PAGE 9
lvcreate(1M) lvcreate(1M) SEE ALSO lvchange(1M), lvdisplay(1M), lvextend(1M), lvmadm(1M), lvmpud(1M), lvreduce(1M), pvchange(1M), intro(7), lvm(7).
PAGE 10
(Notes) A (Notes) lA 10 Hewlett-Packard Company −1− HP-UX 11i Version 3: September 2010