[DRBD-user] Howto prevent write operations on Primary when in WFConnection

Lars Ellenberg lars.ellenberg at linbit.com
Fri Oct 2 09:51:19 CEST 2009


On Thu, Oct 01, 2009 at 10:47:41AM -0700, Joel Jacobson wrote:
> 
> We are about to go live with a DRBD / PostgreSQL installation running on
> Debian 5, 2.6.26-2-amd64.
> 
> Is there a way to prevent write operations on the Primary in case it loses
> connection with the Secondary?
> 
> Why would I want to do that?
> Because if the Primary goes down, while the Secondary is in state
> UpToDate/DUnknown, it is not possible to know for sure if the Primary has
> been modified after the Secondary lost its connection with the Primary.
> But if the Primary would refuse to perform any write operations if the
> replication link goes down to the Secondary, it would be totally safe to
> promote the Secondary to Primary.
> 
> I do of course realize such a configuration would mean the entire system
> would become inaccessible if the Secondary would go down, but that is also
> my wish since we cannot risk losing any data.
> 
> Any ideas are welcome.

DRBD does have various mechanisms to achieve what you want to do,
and yes, it _can_ safely be still available in most cases.

http://www.linbit.com/en/products-services/drbd-consulting/


-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
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