[CentOS] DRBD Problem

Sun Jun 25 07:06:44 UTC 2006
centos at bathnetworks.com <centos at bathnetworks.com>

Again many thanks,

Rob


> On Sat, 2006-06-24 at 13:50 +0100, centos at bathnetworks.com wrote:
>> > On Sat, 2006-06-24 at 11:34 +0100, centos at bathnetworks.com wrote:
>> >> > On Sat, 2006-06-24 at 07:02 +0100, centos at bathnetworks.com wrote:
>> >> >> Hi all,
>> >> >>
>> >> >> I've been wrestling with a problem with drdb and centos. I have
>> >> >> successfully created one drbd resource, but when I try the create
>> a
>> >> 2nd,
>> >> >> I
>> >> >> get an error on one of the nodes:
>> >> >>
>> >> >> Lower device is already mounted.
>> >> >> Command 'drbdsetup /dev/drbd1 disk /dev/hdd1 internal -1'
>> terminated
>> >> >> with
>> >> >> exit code 20
>> >> >>
>> >> >> The partition is not mounted from fstab etc and is newly created
>> with
>> >> >> parted after wiping this disk with dd.
>> >> >>
>> >> >> On the node with the problem I see:
>> >> >>
>> >> >> cat /proc/partitions
>> >> >> major minor  #blocks  name
>> >> >>
>> >> >>    3     0   60034968 hda
>> >> >>    3     1     514048 hda1
>> >> >>    3     2    1534207 hda2
>> >> >>    3     3   57986617 hda3
>> >> >>   22     0  120060864 hdc
>> >> >>   22     1  114688003 hdc1
>> >> >>   22    64  117220824 hdd
>> >> >>   22    65  114688003 hdd1
>> >> >>  253     0  117219800 dm-0
>> >> >>  253     1  114688003 dm-1
>> >> >>  147     0  114556928 drbd0
>> >> >>
>> >> >> On the other node the dm-0 and dm-1 do not occur. Being new to
>> Linux,
>> >> I
>> >> >> am
>> >> >> not sure where these come from. I have tried google, but nothing
>> >> makes
>> >> >> sense.  This maybe a red herring, but dm-1 has the same number of
>> >> blocks
>> >> >> as hdd1 which I am trying to mount so I'm guessing that this is
>> the
>> >> >> cause
>> >> >> of the problem.
>> >> >>
>> >> >> As I have tried changing every thing I can except the mb/processor
>> >> and
>> >> >> reinstalling, I'm really stuck.
>> >> >>
>> >> >> HELP Please.
>> >> >>
>> >> >> Rob
>> >> >>
>> >> >>
>> >> >>
>> >> >
>> >> > I am not an expert on filesystems ... but dm-0 and dm-1 look like
>> raid
>> >> 0
>> >> > or LVM partitions as they have 253 as their Major device number.
>> >> >
>> >> > What does fdisk -l say for that drive (/dev/hdd).
>> >> >
>> >>
>> >> Thanks for the reply.
>> >>
>> >> As far as I am aware, there is no raid or lvm setup on the machine.
>> >>
>> >> disk -l for hdd gives:
>> >>
>> >> Disk /dev/hdd: 120.0 GB, 120034123776 bytes
>> >> 255 heads, 63 sectors/track, 14593 cylinders
>> >> Units = cylinders of 16065 * 512 = 8225280 bytes
>> >>
>> >>    Device Boot      Start         End      Blocks   Id  System
>> >> /dev/hdd1               1       14278   114688003+  83  Linux
>> >>
>> >> Rob
>> >>
>> >
>> > If you are not using raid on purpose, try removing the package dmraid
>> > like this:
>> >
>> > rpm -e dmraid
>> >
>> > then rebooting
>>
>> Johnny,
>>
>> Once again you are proving to be the man.
>>
>> That fixed it. Both resources are up and the 2nd is syncing.
>>
>> One question, I guess I don't need dmraid as I don't have a raid array,
>> but why would it 'grab' the disk as it had never been set in the 1st
>> place?
>>
>
> No idea what caused it to do that ... it is obviously some kind of bug
> if you didn't configure it that way.
>
> I have had issues with the dmraid module in the past, and since I saw
> that it was loading those modules, I figured removing it might help.
>
> Some things to check are ...
>
> 1.  If the machine has RAID settings in the BIOS (and you are not trying
> to do RAID) ... turn them off.
>
> 2.  Be on the look out for dmraid to be reinstalled ... it is in the
> base/core package group in comps.xml (and therefore part of the minimal
> install) ... so it is liable to make it's way back in.
> --------------------------------------------------------
> The purpose of dmraid is to allow the SW RAID controllers that M$
> Winders has tricked people into thinking are real hardware RAIDs to be
> configured as RAID on Linux too ... see this readme:
>
> http://people.redhat.com/heinzm/sw/dmraid/readme
>
> So ... if you have one of those controllers w/RAID set to initialize, it
> will be found and mapped automagically.
>
> Not a good thing ... IMHO ... but I am not as smart as the upstream
> provider :)
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