samba - Oct 2010 - CTDB with 3 nodes and local disks without a dedicated SAN

Hello,

First, sorry, I know that this is by far not 100% samba related but 
since this setup is exclusively for samba + CTDB and as such is no 
ordinary setup, I thought it might be good to ask here.

I'm having a hard time figuring out how to accomplish the following:


I'd like to set up 3 samba nodes clustered with CTDB, with each 
node/machine having its own sets of local disks.
It would be great if 2 machines and/or sets of local disks could fail 
the same time without taking down samba.

Is this only possible using DRBD as suggested in the current Samba 3 book?
As I understand DRBD only allows 2 nodes and an optional 3rd for 
disaster recovery.

Does anyone have any idea or recommendations on how to do this without 
DRBD's limitation of 2 storage nodes?

Thank you very much for any help!

Regards,

Max

Hello,
 you should try iscsi drbd gfs if you think and mix wisely it should
start. THis is, you have on central point of storage where all three nodes
write to and this storage backed up.
My latest try with ctdb did not work on CentOs. The package was brocken.
And I think it is not
possible to cluster a DC.

Greetings 
Daniel 

On Thu, 7 Oct 2010 17:35:17 +0200, Max <mxx2 at mailspot.at>
wrote:
> Hello,
> 
> First, sorry, I know that this is by far not 100% samba related but 
> since this setup is exclusively for samba + CTDB and as such is no 
> ordinary setup, I thought it might be good to ask here.
> 
> I'm having a hard time figuring out how to accomplish the following:
> 
> 
> I'd like to set up 3 samba nodes clustered with CTDB, with each 
> node/machine having its own sets of local disks.
> It would be great if 2 machines and/or sets of local disks could fail 
> the same time without taking down samba.
> 
> Is this only possible using DRBD as suggested in the current Samba 3
book?
> As I understand DRBD only allows 2 nodes and an optional 3rd for 
> disaster recovery.
> 
> Does anyone have any idea or recommendations on how to do this without 
> DRBD's limitation of 2 storage nodes?
> 
> Thank you very much for any help!
> 
> Regards,
> 
> Max

Hi Daniel,

thank you very much for your fast answer!

> you should try iscsi drbd gfs if you think and mix wisely it should
> start. THis is, you have on central point of storage where all three nodes
> write to and this storage backed up.
wouldn't I have one single point of failure then (in terms of HA) or did 
I get something wrong?
> My latest try with ctdb did not work on CentOs. The package was brocken.
Good to know, thanks, I'll compile it from source then as I also run 
CentOS 5.5, wanted to use 3.5 anyway.
> And I think it is not
> possible to cluster a DC.
Could you elaborate more on this?
Do you mean it's not possible to cluster samba acting as a DC? If that's
what you're saying and it's true I must have missed the biggest
point.
>> I'd like to set up 3 samba nodes clustered with CTDB, with each
>> node/machine having its own sets of local disks.
>> It would be great if 2 machines and/or sets of local disks could fail
>> the same time without taking down samba.
>>
>> Is this only possible using DRBD as suggested in the current Samba 3
> book?
The book by Volker Lendecke, Karolin Seeger, Bj?rn Jacke and Michael Adam.
Maybe it's only available in German, I don't know.

Thank you,

Max