1.3.1.6. Upgrading a Fedora installation
The installation program will check to see if you have an existing Fedora installation; if you do, it will offer you the option of upgrading the current system instead of performing a new installation (Figure 1-11).
Figure 1-11. Upgrade option
Choose Install Fedora Core if you want to replace your existing installation, or "Upgrade an existing installation" if you want to upgrade your existing Fedora system to Fedora Core 6. Click Next.
This dialog may appear if you previously started a Fedora installation, but aborted the installation process before it was finished (producing a partially installed system). In that case, choose Install rather than Upgrade to ensure that the new system is complete.
If you have an existing Fedora installation and you want to replace it with Fedora Core 6, but you wish to preserve the data in your home directories, and the home directories have their own filesystem or partition, you can choose Upgrade.
If you choose Install, skip to the next section titled "Performing a New Fedora Installation." Otherwise, the screen shown in Figure 1-12 will appear, asking what you want to do with the bootloader configuration.
Figure 1-12. Bootloader configuration during upgrade
Choose an option based on your current bootloader:
Update boot loader configuration
Use this if your previous installation installed the GRUB bootloader (the default for recent versions of Fedora Core).
Skip boot loader updating
Use this if you are using a third-party bootloader program. You will need to refer to your bootloader documentation to determine how to update the bootloader manually.
Create new boot loader configuration
Select this option if you are using the older LILO bootloader. The installation system will replace LILO with GRUB.
Click Next. After a few seconds, the screen shown in Figure 1-13 will appear.
Figure 1-13. Fedora installation confirmation screen
This is the point of no return. Click Next to proceed with the upgrade, but remember that the upgrade process must run to completion and cannot be safely interrupted. The Fedora installer will analyze the software installed in your existing Fedora system, determine what needs to be updated, and install the new packages.
1.3.1.7. Performing a new Fedora installation
If any of your hard disks are empty and have not been previously used, the warning message displayed in Figure 1-14 will appear. If the drive contains data that you wish to preserve, abort the installation and boot into your existing operating system, figure out why the disk does not show a partition table, and restart the installation. Otherwise, click Yes to continue the installation.
Figure 1-14. Warning about a blank partition table
The installer will now ask what you want to do about partitioning, as shown in Figure 1-15 . In most cases, there are four options available:
Remove all partitions on selected drives and create default layout
This will wipe out everything on the drive and use the entire drive for Fedora Core. Select this option on a new computer or a computer you want to convert for use entirely with Fedora Core. This is also the right option to use when you are installing Linux on a second (or third) disk drive, leaving the software and data on the other drives untouchedbut be careful that only the Fedora Core drive is selected in the list of available disks.
Remove Linux partitions on selected drives and create default layout
Use this option if you are replacing an existing Linux installation and want to leave other operating systems (such as Windows) untouched.
Figure 1-15. Disk and partition strategy selection
Use free space on selected drives and create default layout
If you have unused space on your disk drive, or you have shrunk a Windows partition to free up some space, select this option.
Create custom layout
If you are familiar with partitioning and have special requirementsfor example, you wish to preserve only one filesystem (such as /home ) from a previous Linux installationselect this option.
If you have more than one disk drive installed, you will be able to select the drive(s) to be used for Fedora using the checkboxes in the rectangle labeled "Select the drive(s) to use for this installation." Refer to Table 1-4 for Linux disk names.
At the bottom of this screen, be sure to select the checkbox labeled "Review and modify partitioning layout" so that you will have an opportunity to see the proposed disk layout before it is used. Click Next to continue.
If you have selected an option that involves removing an existing partition, you will see the partition-removal warning shown in Figure 1-16 . Review the information shown, and then click Yes to confirm that you are prepared to remove the partitions listed.
Figure 1-16. Partition removal warning
1.3.1.8. Partitioning layout
By default, Fedora Core uses a system called Logical Volume Management (LVM). A partition managed using LVM is called a physical volume (PV). Storage space from one or more PVs is used to create a pool of storage called a volume group (VG). Out of this pool of storage, one or more virtual partitions are created; each virtual partition is a logical volume (LV). Figure 1-17 illustrates the relationship between these components.
Figure 1-17. Relationship between LVM components
LVM has several advantages over traditional partitioning:
Logical volumes can be resized, enabling you to shift space between filesystems without reinstalling the system.
Logical volumes can span multiple physical volumes, enabling the use of filesystems that are larger than one physical disk.
Additional storage can be added to existing filesystemsfor example, you can add a new disk drive and add that storage space to the home filesystem.
Data can be migrated from one drive to another.
Chapter 6 delves into more detail regarding LVM.
Although logical volumes can be enlarged or reduced at any time, the ext3 filesystem that Fedora uses can be enlarged only while it is in use. It must not be in use when it is reduced in size. This can make it fairly complicated to shrink an ext3 partition. Because it's difficult to determine how much disk space each filesystem will require in the future, it is a good idea to make Fedora filesystems no larger than necessary at first, and then add space to them as required. This avoids the need to reduce the size of one LV in order to increase the size of another.
Unfortunately, the LVM system is too complex to use during the early stages of the booting process, so a system configured to use LVM must also have a small traditional partition for boot files.