Chapter 4. Software RAID Configuration
Read the Appendix on RAID in the Official Red Hat Linux Reference Guide first to tell about RAID and the differences between Hardware RAID versus Software RAID.
Software RAID can be configured during the graphical installation of Red Hat Linux or during a kickstart installation. You can use fdisk or Disk Druid to create your RAID configuration, but these instructions will focus mainly on using Disk Druid to complete this task.
Before you can create a RAID device, you must first create RAID partitions, using the following step-by-step instructions.
 | Tip: If You Use fdisk |
|---|---|
If you are using fdisk to create a RAID partition, remember that instead of creating a partition as type 83, which is Linux native, you must create the partition as type fd (Linux RAID). Also, for best performance, partitions within a given RAID array should span identical cylinders on drives. |
Create a partition. In Disk Druid, choose Add to create a new partition (see Figure 4-1).
You will not be able to enter a mount point (you will be able to do that once you have created your RAID device).
Enter the size that you want the partition to be.
Select Use remaining space if you want the partition to grow to fill all available space on the hard disk. In this case, the partition's size will expand and contract as other partitions are modified. If you make more than one partition growable, the partitions will share the available free space on the disk.
Choose Linux RAID from the Partition Type pull-down menu.
Finally, for Allowable Drives, select the drive on which RAID will be created. If you have multiple drives, all drives will be selected here and you must deselect those drives which will not have the RAID array on them.
Continue these steps to create as many partitions as needed for your RAID setup. Notice that all the partitions do not have to be RAID partitions. For example, in Figure 4-2, only the /home partition is a software RAID device.
Once you have all of your partitions created as RAID partitions, select the Make RAID Device button on the Disk Druid main partitioning screen (see Figure 4-2).
Next, Figure 4-3 will appear, where you can make a RAID device.
First, enter a mount point.
Next, choose the partition type for the partition.
Choose your RAID device. You should choose md0 for your first device, md1 for your second device, and so on, unless you have a specific reason to make it something else. Raid devices range from md0 to md7, and each may only be used once.
Choose your RAID type. You can choose from RAID 0, RAID 1, and RAID 5.
Please Note If you are making a RAID partition of /boot, you must choose RAID level 1 and it must use one of the first two drives (IDE first, SCSI second). If you are not creating a RAID partition of /boot, and you are making a RAID partition of /, it must be RAID level 1 and it must use one of the first two drives (IDE first, SCSI second).
Finally, select which partitions will go into this RAID array (as in Figure 4-4) and then click Next.
At this point, you can continue with your installation process. Refer to the Official Red Hat Linux x86 Installation Guide for further instructions.
