On 30/03/13 7:18, Joakim Ziegler wrote:
> On 29/03/13 10:38, Gordon Messmer wrote:
>> On 03/29/2013 01:23 AM, Joakim Ziegler wrote:
>>> Immediately after getting dropped to rdshell, I looked around in /dev,
>>> which brought me a few surprises...
>>> /dev/mapper contains only "control", that is, "vg_resolve02-lv_root" is
>>> missing.
>> Did you get to look at or for /dev/vg_resolve02 as well?
>>> /dev/root is a symlink to /dev/dm-0
>> Does /dev/dm-0 exist?
>> Does the system boot if you just "exit" from the rdshell? What about if
>> you "vgchange -a y" without changing the symlink?
> I checked this a bit more thoroughly. The status is as follows:
> When I boot up and get dropped to rdshell, neither /dev/root nor
> /dev/vg_resolve02, nor /dev/dm-0 exist. Just exiting at this point drops
> me back into rdshell. Waiting a few minutes makes no difference.
> Doing lvm vgscan finds the volume group, but creates no device nodes.
> Just exiting at this point drops me back into rdshell as well.
> When I do lvm vgchange -ay, /dev/dm-0 is created, /dev/root is created
> as a symlink to it, as well as /dev/vg_resolve02/ with lv_root inside
> it, and /dev/mapper/vg_resolve02-lv_root. I don't need to change the
> symlink or do anything else, if I exit after doing lvm vgchange -ay,
> everything is ok.
>>> That means /dev/root already is correct, so the only thing I'm actually
>>> changing to make the system boot is to scan for volume groups and
>>> activate them.
>>> The big question then becomes: Why do I have to do this manually? How do
>>> I make Dracut (I assume this is Dracut's job) make this automatically?
>> udev should be doing this. And... I was just looking at this again,
>> because the last time I came up with nothing useful. Look at
>> /usr/share/dracut/modules.d/90lvm/64-lvm.rules. If I'm reading this
>> correctly, udev will look for dm-0 in /sys and will not run lvm_scan if
>> it's found. I wonder if it's possible that the /sys nodes are getting
>> set up, but device-mapper isn't setting up the nodes in /dev?
> It turns out I was wrong about dm-0 already existing, it's created on
> vgchange -ay. I'm looking at the file you mention, but I'm afraid I
> don't know LVM well enough to make that much sense of it. From what I
> can tell, it calls lvm_scan for each device, and there's an lvm_scan.sh
> in there that looks like it should be doing lvchange -ay, but if dm-0
> doesn't already exist, I don't think this will do anything, am I wrong?
>> I'm really at a loss... it seems like a much simpler explanation is
>> simply that the devices take so long to detect that init gives up. When
>> you run vgchange, they've had the time they need. That idea is
>> inconsistent with the fact that your dmesg output shows what I assume is
>> the correct devices and partition tables.
>
>> You could try adding "rdinitdebug rdudevdebug" to your kernel command
>> line, but you're going to see a LOT of output, and it's only really
>> going to be meaningful if you've read the /init script that Dracut
>> creates, and understand more or less what it's doing, particularly in
>> the "main_loop" section.
> I can try this, but it might be a bit beyond my area of expertise, I'm
> afraid.
> If I were to just try a brute force approach, what RPM packages should I
> reinstall/update to get all this stuff reinstalled as it was the first
> time I installed the system?
Just bumping this up, any ideas about this? It's a little annoying not
having this box boot by itself...
--
Joakim Ziegler - Supervisor de postproducción - Terminal
joakim@xxxxxxxxxxxxxx - 044 55 2971 8514 - 5264 0864
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