[DRBD-user] Help with initial setup

kevin kempter kevin at kevinkempterllc.com
Thu Oct 9 17:00:54 CEST 2008

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


On Oct 9, 2008, at 8:56 AM, Timh Bergström wrote:

> No need to fdisk-remove the filesystem on /dev/sda2, just force
> creation of meta-data on r0. When the drbd-modules are loaded and
> services are started, you only need to run mkfs.ext3 /dev/drbd1 and
> then mount it wherever you want, mount -t ext3 /dev/drbd1
> /my/mount/point.
>
> You are really missing the point with drbd. You should go back to the
> documentation; http://www.drbd.org/users-guide-emb/ch-configure.html
> and follow the "how-to" there.
>
> //T
>
>
ok, I'm walking thru the doc again.  This time I did a yum install drbd
however, once the rpm install finished I tried this:

# modprobe drbd
FATAL: Module drbd not found.

Is the modprobe bit not required for an RPM install ?

>
> 2008/10/9 kevin kempter <kevin at kevinkempterllc.com>:
>>
>> On Oct 9, 2008, at 8:37 AM, Timh Bergström wrote:
>>
>>> 2008/10/9 kevin kempter <kevin at kevinkempterllc.com>:
>>>>
>>>> On Oct 8, 2008, at 3:36 PM, Florian Haas wrote:
>>>>
>>>>> On 10/08/2008 11:04 PM, Jerry Amundson wrote:
>>>>>>
>>>>>> On Wed, Oct 8, 2008 at 3:33 PM, kevin kempter
>>>>>> <kevin at kevinkempterllc.com>
>>>>>> wrote:
>>>>>>>
>>>>>>> 1) I setup 2 new installs of CentOS v5 (32bit) as VM's via  
>>>>>>> vmware
>>>>>>> server
>>>>>>> on
>>>>>>> a Dell 2900 (quad core, 16Gram, single RAID slice, etc)
>>>>>>>
>>>>>>> Note: I created /stage as a separate ext2 filesystem (mounted  
>>>>>>> from
>>>>>>> /dev/sda2). This is the filesystem I want to replicate with drbd
>>>>>>
>>>>>> That will need to be re-made on the drbd device.
>>>>>
>>>>> Wrong. If you shrink the filesystem (resize2fs) to make room for  
>>>>> DRBD's
>>>>> metadata, you will be able to replicate the existing data without
>>>>> remaking the filesystem. If you need to keep that data.
>>>>>
>>>>> After you have shrunk your filesystem (shrink by 128M to be on  
>>>>> the safe
>>>>> side), you want to do exactly what your original error message  
>>>>> told you,
>>>>> namely use "drbdadm create-md <resource>" to create your metadata.
>>>>>
>>>>> Btw: ext2, being a non-journaling filesystem, is a really bad  
>>>>> choice for
>>>>> HA environments. Use ext3.
>>>>>
>>>>> Florian
>>>>>
>>>>> --
>>>>> : Florian G. Haas
>>>>> : LINBIT Information Technologies GmbH
>>>>> : Vivenotgasse 48, A-1120 Vienna, Austria
>>>>>
>>>>> When replying, there is no need to CC my personal address.
>>>>> I monitor the list on a daily basis. Thank you.
>>>>>
>>>>> LINBIT(R) and DRBD(R) are registered trademarks of LINBIT.
>>>>> _______________________________________________
>>>>> drbd-user mailing list
>>>>> drbd-user at lists.linbit.com
>>>>> http://lists.linbit.com/mailman/listinfo/drbd-user
>>>>
>>>>
>>>> Hi All;
>>>>
>>>> I'm finding no luck with anything I've tried. So I've decided to  
>>>> go back
>>>> to
>>>> ground zero and walk through a proper setup.  A few questions:
>>>>
>>>> I've setup 2 brand new CentOS 5 VM's (via vmware server). I'm  
>>>> wanting to
>>>> use
>>>> internal meta-data to keep things simple.
>>>>
>>>> How do I need to prepare the disk ? this far I've created a  
>>>> partition
>>>> (/drbd_data) as an ext3 filesystem as part of the initial disk
>>>> partitioning
>>>> (in the CentOS install) on both servers.  Is this correct?
>>>
>>> Why? If you do not already have any data that you want to preserve  
>>> in
>>> this space, just dont create a filesystem on it at all, do that when
>>> drbd is set up and started.
>>>
>> Since I already created it, do I need to use fdisk and remove it?
>>
>>>>
>>>> Also, do I need to unmount these /drbd_data file systems before
>>>> attempting
>>>> to startup drbd ?
>>>
>>> It should not be mounted as it should not contain a filesystem,  
>>> see above.
>>>
>>>>
>>>>
>>>> Next steps:
>>>> 1) install the drbd RPM's on both servers
>>>>
>>>> 2) modprobe drbd (on both servers)
>>>>
>>>> 3) create the /etc/drbd.conf file on both servers
>>>>
>>>> 4) run drbdadm create-md 'resource' on the master node
>>>>
>>>> 5) run drbdadm attach 'resource' on the master node
>>>
>>> After this step, you should create the filesystem on the DRBD  
>>> resource
>>> (ie. mkfs.ext3 (read manual for options) /dev/drbd1) not /dev/sda2.
>>> Then connect it - then mount the DRBD-resource. And you only have to
>>> create the filesystem on the master node, which will be replicated  
>>> to
>>> the slave-node with drbd.
>>>
>> In the drbd.conf file the on resource entries (in the samples) show  
>> device
>> and disk entries that are both /dev/xx I'm confused on the  
>> difference.
>> If I create an ext3 fs at /dev/sda2 how do I associate this device  
>> with
>> something like /dev/drbd1 ? Is /dev/drbd1 simply the mount point ?
>>
>>
>>>>
>>>> 6) run drbdadm connect 'resource' on the master
>>>>
>>>>
>>>> Previously when I tried to run step 4 I got error messages,  
>>>> trying to use
>>>> a
>>>> minimal config using internal meta data
>>>>
>>>> Does the above sound correct ? Am I missing anything ?
>>>>
>>>> Thanks in advance
>>>>
>>>>
>>>> _______________________________________________
>>>> drbd-user mailing list
>>>> drbd-user at lists.linbit.com
>>>> http://lists.linbit.com/mailman/listinfo/drbd-user
>>>>
>>>
>>>
>>>
>>> --
>>> Timh Bergström
>>> System Administrator
>>> Diino AB - www.diino.com
>>> :wq
>>
>>
>
>
>
> -- 
> Timh Bergström
> System Administrator
> Diino AB - www.diino.com
> :wq




More information about the drbd-user mailing list