Reducing the physical extent size increases the size of the LVM data structures but gives a finer granularity for assigning storage to logical volumes. Increasing the physical extent size slightly reduces the LVM overhead, increasing performance.
Select the checkbox of all of the physical volumes you wish to use in this volume group.
The next step is to create a logical volume to hold each filesystem you wish to create. Table 10-2 contains a list of recommended filesystems.
Table 10-2. Recommended filesystems for Fedora Core
| Mount point | Recommended size | Notes |
|---|---|---|
| / | 10 GB | Required |
| /home | 10 GB or more, depending on how much data your users will be personally storing | Strongly recommended for any system where users will be logging in on the console or via remote SSH access (e.g., desktop systems, servers with personal user accounts), and systems that are acting as file servers for personal files such as a Samba server (see Lab 7.1, "Configuring Samba to Share Files with Windows Systems"). By separating the users' home directories onto a separate filesystem, you can reinstall the operating system in the future without affecting users' files. |
| /var | 2 GB to 1 TB depending on the applications in use | The /var filesystem holds data that is variable but that is not stored in the users' home directories for example, databases, email, web pages, and queued print requests. Creating a separate filesystem segregates it for backup and makes it easier to reinstall the operating system without affecting this data. |
To create each logical volume and filesystem, click the Add button at the bottom of the screen to access the Make Logical Volume window shown in Figure 10-16 .
Figure 10-16. Make Logical Volume window
Enter the chosen Mount Point and a descriptive logical volume name; then enter the desired size (leaving the File System Type set to the default, "ext3"). Click OK to return to the Make LVM Volume Group window; note that the LV size you entered is rounded to a multiple of the physical extent size in the Logical Volumes display.
Repeat this process for the other logical volumes.
It is best to leave some space within the VG unassigned so that you can use LVM snapshots and so that you can add space to a crowded filesystem without having to unmount another filesystem to reduce its size.
Finally, create a swap LV by clicking on the Add button in the Make LVM Volume Group window; when the Make Logical Volume window appears ( Figure 10-16 ), set the File System Type to "swap," and enter the desired swap size. Although traditional wisdom dictates a swap size twice as large as the system memory, it's reasonable to give a system with more memory less swapspace, and a system with less memory more swapspace. If in doubt, use the traditional figure as a starting point, since it can be changed later. The swapspace should be at least as large as the installed RAM (Disk Druid will warn you if it is not).
Once you have configured all of the logical volumes, click OK in the Make LVM Volume Group window, and then click Next in the main Disk Druid window. Proceed with the installation as outlined in Chapter 1 .
10.2.2. How Does It Work?
Like most of the Fedora system administration tools, Disk Druid (and Anaconda) are largely written in Python and interface with other open source tools such as parted , libparted , and lvm .
The purpose of Disk Druid is to improve the installation experience by taking care of many of the partitioning, RAID configuration, and LVM setup details automatically.
While other partitioning tools such as fdisk and parted require the user to keep track of partition numbers and starting and ending locations, and to use cylinders as a unit of measure, Disk Druid handles partition numbering automatically (even including drive selection, where appropriate).
On a PC, the first sector of each disk drive stores a Master Boot Record (MBR). The last 64 bytes of the MBR contain a partition table , which can hold a maximum of four entries; each entry contains a starting and ending cylinder number, boot flag, and partition type code. If more than four partitions are required, one of the MBR entries is configured to point to an extended partition , which contains its own extended partition table . The extended partition table can contain a maximum of one partition entry and one additional extended partition entry, both of which must be located within the extended partition. In this way, any number of partitions may be created.
10.2.3. What About...
10.2.3.1. ...disk partitions on non-PC systems?
There are many different types of disklabels , or disk partition table types, used on different types of systems. Of particular note for Fedora users is the fact that Mac systems use a different, more capable disk partition table. parted is able to display, create, and manipulate nine different types of disklabels, including those for IBM AIX Unix systems, Macs, PCs (called msdos in the parted documentation), Sun systems, and many others.
10.2.4. Where Can I Learn More?
The manpages for parted , fdisk , lvm , and mdadm
The Anaconda project page: http://fedora.redhat.com/projects/anaconda-installer/
The Anaconda Wiki page: http://fedoraproject.org/wiki/Anaconda
10.3. Preparing Alternate Installation Media
The Fedora Core installation process is usually booted from CD or DVD, but it may also be booted from a USB flash disk or hard disk drive, or from a PXE boot server.
In addition, Fedora Core permits the use of an FTP or HTTP server as the package source during installation.
These alternate installation media must be specially prepared before use.
10.3.1. How Do I Do That?
Before preparing alternate boot media, check that the target system can boot from the media you wish to use. Examine the BIOS of the system on which Fedora will be installed to see if it supports booting from a USB flash drive or a PXE server; if not, select a different installation medium.