On 09/11/2010 16:35, Martin Cracauer wrote:
John Robinson wrote on Sun, Nov 07, 2010 at 09:39:03PM +0000:
[...]
That's the other difference between 0.90 and 1.x metadata. In-kernel
auto-assembly is only available for 0.90, and Neil Brown has made it
clear that there will never be in-kernel auto-assembly for 1.x, and
explained at length why. You need mdadm to start 1.x arrays, in your
initrd if your root filesystem is on such an array. All modern distros
create suitable initrds automatically. We are moving towards having
array assembly handled by udev invoking mdadm as devices are discovered.
That's good it know. I still think that udev is a plot to destroy
Linux as we know it so I guess I'm gonna recreate this particular
array :-)
What do you do if you plug in a couple harddrives that have arrays on
them that you do not want assembled? Right now you just set them to a
partition type other than autodetect and you are good.
You can still do that, but the "right" way to do it (I think) is to use
the AUTO keyword and only to include the arrays you want assembled at
boot time in the mdadm.conf that goes into the initrd.
What do you do when udev maintainers in distributions screw up and
replace good udev entires with bad ones? That happened to me
repeatedly and is the major reason for the attitude above.
Oh dear, you've had a bad experience there then. I like udev. I disliked
the old huge /dev with gazillions of entries for devices you don't have,
and you still ended up using MAKEDEV or mknod whenever you added
something new. I did say "moving towards" because udev-based assembly
isn't 100% there yet, and I don't think any distros are trying to use
it. But the other great thing we will get with udev is hotplugging,
including the option to configure in advance auto-rebuilding of arrays,
something that hardware RAID adapters have always had but we still don't
for software RAID.
Cheers,
John.
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