Red Hat GLOBAL FILE SYSTEM 5.0, Руководство администратора

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the physical volume.
2.5. Removing Physical Volumes
If a device is no longer required for use by LVM, you can remove the LVM label with the
pvremove
command. Executing the
pvremove
command zeroes the LVM metadata on an empty
physical volume.
If the physical volume you want to remove is currently part of a volume group, you must remove
it from the volume group with the
vgreduce
command, as described in Section 3.5, “Removing
Physical Volumes from a Volume Group” .
# pvremove /dev/ram15
Labels on physical volume "/dev/ram15" successfully wiped
3. Volume Group Administration
This section describes the commands that perform the various aspects of volume group
administration.
3.1. Creating Volume Groups
To create a volume group from one or more physical volumes, use the
vgcreate
command.
The
vgcreate
command creates a new volume group by name and adds at least one physical
volume to it.
The following command creates a volume group named
vg1
that contains physical volumes
/dev/sdd1
and
/dev/sde1
.
vgcreate vg1 /dev/sdd1 /dev/sde1
When physical volumes are used to create a volume group, its disk space is divided into 4MB
extents, by default. This extent is the minimum amount by which the logical volume may be
increased or decreased in size. Large numbers of extents will have no impact on I/O
performance of the logical volume.
You can specify the extent size with the
vgcreate
command if the default is not suitable with
the
-s
argument. You can put limits on the number of physical or logical volumes the volume
group can have by using the
-p
and
-l
arguments of the
vgcreate
command.
By default, a volume group allocates physical extents according to common-sense rules such as
not placing parallel stripes on the same physical volume. This is the
normal
allocation policy.
You can use the
--alloc
argument of the
vgcreate
command to specify an allocation policy of
contiguous
,
anywhere
, or
cling
.
Chapter 4. LVM Administration with CLI Commands
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