[DRBD-user] Help with initial setup

kevin kempter kevin at kevinkempterllc.com
Thu Oct 9 17:03:43 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 9:00 AM, kevin kempter wrote:

>
> 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.

My mistake -- I spoke (emailed) too soon. Apologies.
>
>
> 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
>




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