Hi experts,

Now, I am practicing the Software RAID on the Linux OS. I have serval confusions about the how to migrate an existing OS(or the boot partition or other partitions) to an Array.

My testing ENV as follows:

Linux installed on VMware, kernel 2.6.9-5(RedHat AS4)
Using the default RAID tool --- mdadm as Software RAID
There are two SCSI disks with same size (since the VMware using the SCSI as the OS disks)


First question:
If I want to make the scsi and raid1 module builtin the kernel without downloading the kernel source code, should I use the following command to use the current kernel:
mkinitrd --builtin=scsi_mod,raid1 /boot/xxxxx.img 2.6.9-5.EL
and then only modify the initrd field of grub.conf file with the new image file name?

Second question:
Regrading the device sda, it has already been formated as ext3 filesystem and installed OS file on it. if I change the partition type via "fdisk", can this operation destroy the whole data files?

Third question:
are there some detail sepcifications to demostrate my scenarios? who can help me to give some links about them which I can follow to study the RAID system?

Thanks for everyone giving great feedback.

Is there anyone giving a helpful replay?

My advice may or may not be helpful...

IMHO, it's simply not a good idea to put an OS partition in a software RAID. Unlike a hardware RAID, a software RAID will not give you the functionality of simply replacing a hard drive and "it works". It will complicate recovery efforts, if anything.

If you want to experiment with software RAID, I think it's more realistic to assume a scenario where the OS is in a normal partition while data is kept in RAID partitions.

My prefered method is to set up backup OS partitions on all of the hard drives. When I make major changes to the "live" OS partition, I copy the live OS partition to the backups. I have GRUB set up on each drive. Thus, in case of failure I can swap to a backup drive.

My method doesn't provide continuous uptime, so it's not suitable for a mission critical server that needs constant operation. IMHO, software RAID isn't the solution for those mission critical servers. If you need 100% uptime, you need hardware RAID and/or redundant clustering.