lvcreate.1m (2010 09)

l
lvcreate(1M) lvcreate(1M)
not have a physical volume group defined.
n Do not set a strict or PVG-strict allocation policy. Mirrors of a logi-
cal extent can share the same physical volume.
-t timestamp 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.
This option is only applicable for the snapshot volume.
Striped Logical Volume Considerations
Striped and mirrored logical volumes are supported. A logical volume striped across stripes physical
volumes is allocated in sets of stripes logical extents. A set corresponds to stripes physical extents if the
volume is not mirrored or to stripes *(mirror_copies + 1) physical extents if the volume is mirrored.
stripes is the number of physical volumes the logical volume is striped across. It is set with the option
-i
stripes . mirror_copies is the number of mirror copies allocated for each logical extent. It is set with the
-m option. The user data is striped across stripes physical extents of the set, and each of these extents is
mirrored on mirror_copies other physical extents of the same set. Striped logical volumes are only allo-
cated using the strict or PVG-strict allocation policies. Each physical extent of a given set is allocated on
a different physical volume in the volume group.
The total number of physical extents of a striped logical volume is always a multiple of stripes (or stripes
*(mirror_copies + 1) if the volume is mirrored).
A minimum of stripes (or stripes *(mirror_copies + 1) if the volume is mirrored) physical volumes with
adequate free space and meeting the allocation policy is needed to allocate a striped logical volume.
Shared Volume Group Considerations
For volume group version 1.0 and 2.0,
lvcreate cannot be used if the volume group is activated in
shared mode. For volume groups version 2.1 (or higher), lvcreate can be performed when activated in
either shared, exclusive, or standalone mode.
Note that the
lvmpud daemon must be running on all the nodes sharing a volume group activated in
shared mode. See lvmpud (1M).
When
lvcreate is issued, it creates the logical volume device special files on all the nodes sharing the
volume group. The device special files are created with the same name on the nodes sharing the volume
group.
When a node wants to share the volume group, the user must first execute a
vgimport
if logical volumes
were created at the time the volume group was not activated on that node.
The logical volumes device special files should have the same name on all the nodes sharing the volume
group.
If PVG-strict allocation policy is set, the
/etc/lvmpvg file used is the one on the system where the com-
mand is issued.
LVM shared mode is currently only available in Serviceguard cluster.
Note that snapshot logical volume creation is not supported when the volume group is activated in shared
mode.
EXTERNAL INFLUENCES
Environment Variables
LANG determines the language in which messages are displayed.
If
LANG is not specified or is null, it defaults to "C" (see lang (5)).
If any internationalization variable contains an invalid setting, all internationalization variables default
to "C" (see environ (5)).
EXAMPLES
Create a logical volume in volume group /dev/vg02:
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