Software Raid And Lvm - HP xw3400 User Manual

6. Create a RAID device by selecting the "RAID" option in the main partitioning menu, then
choosing "Create a RAID Device" from the "RAID Options" screen, and configuring as
desired.
7. Continue with setup as normal.
At this point, finish with the initial installation and configuration of your workstation. You should now
have a partition that will be made bootable on each hard disk in the RAID array. You can verify your
current disk setup by running the df command in a terminal window.
You can now mirror the original /boot partition to the partitions you created on the other drives.
8. For each other bootable partition, copy the contents of the /boot partition to the new
partition as follows:
cp ña /boot/* /boot1/
If your other bootable partition is named /boot1.
9. Repeat step 8 for each bootable partition until each hard drive in the RAID array has been
configured as such.
10. The final step is to edit the /etc/fstab file to allow the system to boot without the original
/boot partition. Comment out the line with the /boot partition by inserting a # at the
beginning of that line in the file. The system will now be able to boot to any of the other
drives in the RAID array if the first disk should fail.
Tip:
While you do not need to have /boot mounted for the system to boot
normally, you will need to mount it if you are running a kernel update. After
the update is complete, repeat these steps to mirror the new /boot
partition to the bootable partitions on the other drives. After this is done,
the /boot partition can safely be removed from the /etc/fstab file
again.

Software RAID and LVM

Software RAID can be used with the Linux LVM, or Logical Volume Manager, to provide a greater
degree of flexibility with regard to the setup of the filesystem. The LVM provides a level of abstraction
of the physical disks in a filesystem, making it easier to manage. It works by grouping physical disks
into a volume group, which can then be partitioned into logical volumes. These logical volumes
behave much like ordinary disk block devices, except that logical volumes can be dynamically grown,
shrunk, and/or moved without rebooting the system or entering into maintenance/standalone mode.
In general, it adds a layer of abstraction between filesystem mount points such as / or /usr, and
hard disk devices such as /dev/hda1 or /dev/sdb2.
The benefit of using LVM is the flexibility of being able to add or remove physical hard drives or move
data between existing drives without disrupting the filesystem or users. LVM cannot be used to
dynamically resize RAID devices, nor can physical drives be simply added and removed from a RAID
array as they could while using LVM without RAID. There are still benefits to using software RAID with
LVM, which can be implemented using the following steps:
1. Set up RAID partitions using Disk Druid, fdisk, or whatever partition manager you
prefer.
2. Create the RAID array, either during installation using the Anaconda installer, or manually
after installation. Any supported RAID level can be used with LVM, since neither software
RAID nor LVM knows about the other.
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