The following section explains how to manually configure LVM for
Red Hat Enterprise Linux. Because there are numerous ways to manually configure a system
with LVM, the following example is similar to the default configuration
done in Section 8.1 Automatic Partitioning.
On the Disk Partitioning Setup screen, select
Manually partition with Disk Druid.
In a typical situation, the disk drives are new, or formatted
clean. The following figure, Figure 8-2,
shows both drives as raw devices with no partitioning configured.
Figure 8-2. Two Blank Drives, Ready For Configuration
The /boot/ partition cannot reside on an LVM
volume group because the GRUB boot loader cannot read it.
Select /boot from the Mount
Point pulldown menu.
Select ext3 from the File System
Type pulldown menu.
Select only the sda checkbox from the
Allowable Drives area.
Leave 100 (the default) in the Size
Leave the Fixed size (the default) radio
button selected in the Additional Size
Select Force to be a primary partition to
make the partition be a primary partition. A primary partition is
one of the first four partitions on the hard drive. If unselected,
the partition is created as a logical partition. If other
operating systems are already on the system, unselecting this
option should be considered. For more information on primary
versus logical/extended partitions, refer to the appendix section
of the Red Hat Enterprise Linux Installation Guide.
Refer to Figure 8-3 to verify your inputted values:
Figure 8-3. Creation of the Boot Partition
Click OK to return to the main screen. The
following figure displays the boot partition correctly set:
Figure 8-4. The /boot/ Partition Displayed
Once the boot partition is created, the remainder of all disk space
can be allocated to LVM partitions. The first step in creating a
successful LVM implementation is the creation of the physical
Select physical volume (LVM) from the
File System Type pulldown menu as shown in Figure 8-5.
Figure 8-5. Creating a Physical Volume
You cannot enter a mount point yet (you can once you have created
all your physical volumes and then all volume groups).
A physical volume must be constrained to one drive. For
, select the drive on which
the physical volume are created. If you have multiple drives, all
drives are selected, and you must deselect all but one drive.
Enter the size that you want the physical volume to be.
Select Fixed size to make the physical volume
the specified size, select Fill all space up to
(MB) and enter a size in MBs to give range for the
physical volume size, or select Fill to maximum
allowable size to make it grow to fill all available
space on the hard disk. If you make more than one growable, they
share the available free space on the disk.
Select Force to be a primary partition if you
want the partition to be a primary partition.
Click OK to return to the main screen.
Repeat these steps to create as many physical volumes as needed for your
LVM setup. For example, if you want the volume group to span over
more than one drive, create a physical volume on each of the drives. The
following figure shows both drives completed after the repeated process:
Figure 8-6. Two Physical Volumes Created
Once all the physical volumes are created, the volume groups can
Click the LVM button to collect the
physical volumes into volume groups. A volume group is basically a
collection of physical volumes. You can have multiple logical volume
groups, but a physical volume can only be in one volume group.
There is overhead disk space reserved in the logical volume
group. The summation of the physical volumes may not equal the size
of the volume group; however, the size of the logical volumes shown is
Figure 8-7. Creating an LVM Volume Group
Change the Volume Group Name if
All logical volumes inside the volume group must be allocated in
physical extent units. By default, the physical
extent is set to 32 MB; thus, logical volume sizes must be divisible by
32 MBs. If you enter a size that is not a unit of 32 MBs, the
installation program automatically selects the closest size in units
of 32 MBs. It is not recommended that you change this setting.
Select which physical volumes to use for the volume group.
Create logical volumes with mount points such as
/, /home/, and swap
space. Remember that /boot cannot be a logical
volume. To add a logical volume, click the Add
button in the Logical Volumes section. A dialog
window as shown in Figure 8-8 appears.
Figure 8-8. Creating a Logical Volume
Repeat these steps for each volume group you want to create.
You may want to leave some free space in the
logical volume group so you can expand the logical volumes later. The
default automatic configuration does not do this, but this manual
configuration example does — approximately 1 GB is left as free space for future
Figure 8-9. Pending Logical Volumes
Click OK to apply the volume group and all
associated logical volumes.
The following figure shows the final manual configuration:
Figure 8-10. Final Manual Configuration