Homme wrote:
On Thursday, Aug 7, 2003, at 14:15 Europe/Amsterdam, Dave Anderson wrote:
Switching to MD from ataraid, I'd advise to just let the kernel see two drives and forget about ataraid if you want to go to MD. Ataraid devices are scary and currently do not properly flush hd write caches before shutdown/reboot. They should be avoided unless you have a multiboot system with windows and want to be able to use the drives on the ataraid while running linux.
Thanks for the detailed answer. So on a single Linux box, with no
other OS, md really is the better choice over ataraid.
Will I be able to just disable the raid array, see two (identical)
drives and set up md raid?
If you do not load the ataraid driver and do not set up raid in the controller bios, it
*should* act as a simple ide controller showing you two drives. Be aware you will
most likely have to repartition your disk(s) and loose all data on them.
Be aware. As I stated before, to my best knowledge (which is a bit dated) it is not
possible to set up a decent md configuration that supports booting from just one
of the two disks, replacing one of the two disks while running or rebuilding the
array while still running production.
This has not been an issue for a long time. You should make sure of the following:
1)Install your boot loader to both drives. This just works with lilo, and I'm told can be done with grub.
2)Make sure /boot is a raid1 array.
3)Make sure your swap is on md devices as well.
The ide driver doesn't really support hot swaping so you will have to reboot to replace a drive. You can start a rebuild of an array in the background with the mdtools.
Again, I'd love to be proven wrong in this because
I use expensive hardware controllers quite frequently to overcome these problems.
If you want to be certain you can do all of these, either verify these conditions yourself,
or go for 3ware hardware IDE raid or similar.
Homme
-- Once you have their hardware. Never give it back. (The First Rule of Hardware Acquisition) Sam Flory <sflory@xxxxxxxxxxxx>
