Official Red Hat Linux Administrators Guide

If you chose automatic partitioning and did not select Review, please skip ahead to the “Adding Partitions” section of this appendix. If you chose automatic partitioning and selected Review, you can either accept the current partition settings (click Next) or modify the setup using Disk Druid, the manual partitioning tool. If you chose Manually partition with fdisk, please skip ahead to the “Partitioning with fdisk” section.

At this point, you must tell the installation program where to install Red Hat Linux. This is done by defining mount points for one or more disk partitions in which Red Hat Linux will be installed. You may also need to create and/or delete partitions at this time (refer to Figure A-16).

Figure A-16: Partitioning with Disk Druid

The partitioning tool used by the installation program is Disk Druid. With the exception of certain esoteric situations, Disk Druid can handle the partitioning requirements for a typical installation.

Graphical Display of Hard Drive(s)

Disk Druid offers a graphical representation of your hard drive(s). Using your mouse, click once to highlight a particular field in the graphical display. Double-click to edit an existing partition or to create a partition from existing free space.

Above the display, you will see the drive name (such as /dev/hda), the geom (which shows the hard disk’s geometry and consists of three numbers representing the number of cylinders, heads, and sectors as reported by the hard disk), and the model of the hard drive as detected by the installation program.

Disk Druid’s Buttons

The various buttons described in the following list control Disk Druid’s actions. They are used to change the attributes of a partition (for example, the file system type and mount point) and also to create RAID devices. Buttons on this screen are also used to accept the changes you have made, or to exit Disk Druid. For further explanation, take a look at each button in order:

• New: Used to request a new partition. When selected, a dialog box appears containing fields (such as mount point and size) that must be filled in.

• Edit: Used to modify attributes of the partition currently selected in the Partitions section. Selecting Edit opens a dialog box. Some or all of the fields can be edited, depending on whether or not the partition information has already been written to disk.

• You can also edit free space as represented in the graphical display to create a new partition within that space. Either highlight the free space and then select the Edit button, or double-click on the free space to edit it.

• Delete: Used to remove the partition currently highlighted in the Current Disk Partitions section. You will be asked to confirm the deletion of any partition.

• Reset: Used to restore Disk Druid to its original state. All changes made will be lost if you Reset the partitions.

• RAID: Used to provide redundancy to any or all disk partitions. It should be used only if you have experience using RAID. To read more about RAID, refer to Chapter 11. To make a RAID device, you must first create software RAID partitions. Once you have created two or more software RAID partitions, select RAID to join the software RAID partitions into a RAID device.

• LVM: Allows you to create an LVM logical volume. The role of LVM (Logical Volume Manager) is to present a simple, logical view of underlying physical storage space, such as a hard drive(s). LVM manages individual physical disks — or, to be more precise, the individual partitions present on them. It should be used only if you have experience using LVM. To create an LVM logical volume, you must first create partitions of the type “physical volume (LVM).” Once you have created one or more physical volume (LVM) partitions, select LVM to create an LVM logical volume.

Partition Fields

Above the partition hierarchy are labels that present information about the partitions you are creating. The labels are defined as follows:

• Device: This field displays the partition’s device name.

• Mount Point/RAID/Volume: A mount point is the location within the directory hierarchy at which a volume exists; the volume is “mounted” at this location. This field indicates where the partition will be mounted. If a partition exists but is not set, you need to define its mount point. Double-click on the partition or click the Edit button.

• Type: This field shows the partition’s type (for example, ext2, ext3, or vfat).

• Format: This field shows if the partition being created will be formatted.

• Size (MB): This field shows the partition’s size (in MB).

• Start: This field shows the sector on your hard drive where the partition begins.

• End: This field shows the sector on your hard drive where the partition ends.

• Hide RAID device/LVM Volume Group members: Select this option if you do not want to view any RAID device or LVM Volume Group members that have been created.

Recommended Partitioning Scheme

Unless you have a reason for doing otherwise, Red Hat recommends that you create the following partitions:

• A /swap partition (at least 32MB) — swap partitions are used to support virtual memory. In other words, data is written to a swap partition when there is not enough RAM to store the data your system is processing. The size of your swap partition should be equal to twice your computer’s RAM, or 32MB, whichever amount is larger. For example, if you have 1GB of RAM or less, your swap partition should be at least equal to the amount of RAM on your system, up to two times the RAM. For more than 1GB of RAM, 2GB of swap is recommended. Creating a large swap space partition will be especially helpful if you plan to upgrade your RAM at a later time.

• A /boot partition (75MB) — the partition mounted on /boot contains the operating system kernel (which allows your system to boot Red Hat Linux), along with files used during the bootstrap process. Because of the limitations of most PC BIOSes, creating a small partition to hold these files is a good idea. For most users, a 75MB boot partition is sufficient.

  Warning

  Do not create your /boot partition as an LVM partition type. The boot loaders included with Red Hat Linux cannot read LVM partitions and you will not be able to boot your Red Hat Linux system.

  Warning

  If your hard drive is more than 1024 cylinders (and your system was manufactured before the turn of the century), you may need to create a /boot partition if you want the / (root) partition to use all of the remaining space on your hard drive.

• A root partition (1.5–4.5GB) — this is where / (the root directory) will be located. In this setup, all files (except those stored in /boot) are on the root partition. A 1.5GB root partition will permit the equivalent of a personal desktop or workstation installation (with very little free space), while a 4.5GB root partition will let you install every package.

Adding Partitions

To add a new partition, select the New button. A dialog box appears (see Figure A-17).

Figure A-17: Creating a new partition

• Mount Point: Enter the partition’s mount point. For example, if this partition should be the root partition, enter /; enter /boot for the /boot partition, and so on. You can also use the pull-down menu to choose the correct mount point for your partition.

• File System Type: Using the pull-down menu, select the appropriate file system type for this partition. For more information on file system types, see the next section, “File System Types.”

• Allowable Drives: This field contains a list of the hard disks installed on your system. If a hard disk’s box is highlighted, then a desired partition can be created on that hard disk. If the box is not checked, then the partition will never be created on that hard disk. By using different checkbox settings, you can have Disk Druid place partitions as you see fit, or let Disk Druid decide where partitions should go.

• Size (Megs): Enter the size (in megabytes) of the partition. Note, this field starts with 100MB; unless this is changed, only a 100MB partition will be created.

• Additional Size Options: Choose whether to keep this partition at a fixed size, to allow it to “grow” (fill up the available hard-drive space) to a certain point, or to allow it to grow to fill any remaining hard-drive space available. If you choose Fill all space up to (MB), you must give size constraints in the field to the right of this option. This allows you to keep a certain amount of space free on your hard drive for future use.

• Force to be a primary partition: Select whether the partition you are creating should be one of the first four partitions on the hard drive. If unselected, the partition created will be a logical partition. See the “Recommended Partitioning Scheme” section earlier in this appendix for more information.

• Check for bad blocks: Checking for bad blocks can help prevent data loss by locating the bad blocks on a drive and making a list of them to prevent use of them in the future. If you wish to check for bad blocks while formatting each file system, please make sure to select this option. Selecting Check for bad blocks may dramatically increase your total installation time. Since most newer hard drives are quite large, checking for bad blocks may take a long time; the length of time depends on the size of your hard drive. If you choose to check for bad blocks, you can monitor your progress on virtual console #6.

• Ok: Select Ok once you are satisfied with the settings and wish to create the partition.

• Cancel: Select Cancel if you do not want to create the partition.

File System Types

Red Hat Linux allows you to create different partition types, based on the file system they will use. The following is a brief description of the different file systems available, and how they can be utilized.

• ext2 — An ext2 file system supports standard UNIX file types (regular files, directories, symbolic links, etc). It provides the ability to assign long file names, up to 255 characters. Versions prior to Red Hat Linux 7.2 used ext2 file systems by default.

• ext3 — The ext3 file system is based on the ext2 file system and has one main advantage — journaling. Using a journaling file system reduces time spent recovering a file system after a crash as there is no need to fsck the file system. The ext3 file system will selected by default and is highly recommended.

  Note

  The fsck application is used to check the file system for metadata consistency and optionally to repair one or more Linux file systems.

• physical volume (LVM) — Creating one or more physical volume (LVM) partitions allows you to create an LVM logical volume.

• software RAID — Creating two or more software RAID partitions allows you to create a RAID device. For more information regarding RAID, refer to Chapter 11.

• swap — Swap partitions are used to support virtual memory. In other words, data is written to a swap partition when there is not enough RAM to store the data your system is processing.

• vfat — The VFAT file system is a Linux file system that is compatible with Windows 9x/NT long file names on the FAT file system.

Editing Partitions

To edit a partition, select the Edit button or double-click the existing partition.

Deleting a Partition

To delete a partition, highlight it in the Partitions section and click the Delete button. You will be asked to confirm the deletion. Skip to the “Boot Loader Configuration” section for further installation instructions.