Managing RAID on Linux - Derek Vadala [100]
Now that the new ataraid kernel is built and installed, add a stanza to /etc/lilo.conf.
image=/boot/bzImage
label=ataraid
read-only
root=/dev/ataraid/d0p2
Note that the root line contains a nonstandard device entry. The ataraid driver uses the /dev/ataraid directory to organize the devices it manages. In this case, the root partition is located on the first array's (d0) second partition (p2). In general, ataraid devices use the format /dev/ataraid/dXpN, where X is the array number and N is the partition number.
While you're editing /etc/lilo.conf, check the boot line to make certain it points to the current system disk (/dev/sda or /dev/sda1, in most cases) because at this point, you're still using the FastTrak driver. After you reboot the system, you can change the boot line to reflect the ataraid naming scheme, but for now, you need to be certain that the boot record is being written to the proper place. Since this is a new system, the installer might have created an /etc/lilo.conf file with a boot line that refers directly to one of the component disks. That means you could unknowingly run /sbin/lilo and write a boot sector that will hang the system on the next reboot. Don't forget to either change the default line in /etc/lilo.conf to specify the new ataraid entry, or remove the default line altogether and make sure the ataraid stanza appears first.
You don't need to take any additional steps if you merely added support for a Promise RAID controller to an existing system. However, you will need to restart the system and use the FastBuild utility to define arrays. After you reboot, you can access any new arrays, using the naming scheme outlined earlier. Just create a filesystem as you would with any normal block device.
Additional steps for new systems
Change the /etc/fstab entries for your system partitions if you are not using partition labels. If you're using partition labels, you don't need to make any changes to /etc/fstab right now.
Execute /sbin/lilo and reboot the system. The system will restart, using the ataraid driver. If an error occurs, just reboot with the original kernel and double-check each step that I have outlined. After the system restarts, you can execute the mount command, without any options, to ensure that the proper driver is in use and that the partitions have been correctly mounted.
# mount
/dev/ataraid/d0p2 on / type ext3 (rw)
none on /proc type proc (rw)
/dev/ataraid/d0p1 on /boot type ext3 (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
The proper device entries are listed in this output: /dev/ataraid/d0p2 for the root filesystem and /dev/ataraid/d0p1 for /boot.
Next, edit /etc/fstab and change your swap partition's entry to reflect the ataraid naming style. My original swap partition was /dev/sda3, so I'll change its /etc/fstab entry to /dev/ataraid/d0p3. Since the change to the swap device was made after the system started, execute swapon -a to activate the swap space.
Finally, edit /etc/lilo.conf so that the boot line references the ataraid device instead of the /dev/sdN device used by the FastTrak driver. In this case, we'll change the boot line to boot=/dev/ataraid/d0, meaning that the boot sector should be installed onto the first array defined on the controller.
Converting an Existing Standalone Disk to a Mirror
Because there are so many problems associated with the Promise installation process, I recommend upgrading your system from a standalone disk to a mirror via a backup and restore procedure.
Post-Installation Array Management
There are no user-space management tools for Linux. While Promise does provide some Microsoft Windows management packages, they have unfortunately not been ported to Linux.