[DRBD-user] DRBD 9 or DRBD 8.4 for Dual Primary

[Robert Altnoeder]

On 08/23/2018 10:15 PM, Daniel Ragle wrote:
> Greetings,
>
> I'm setting up my first DBRD pair for testing and curious as to which
> version I should use.
>
> I definitely need a dual primary system, as I need the load balancing
> between the two nodes. I may need to move to a multiple-node (3+)
> infrastructure in the future.

I'll leave commenting on the stability of dual primary setups with DRBD
9.0.x to the core DRBD developers, as I am unsure of its current status.

But anyway, a dual/multiple primary setup for load balancing typically
only makes sense if the reason for the load-balancing is not I/O, but
e.g. CPU or memory resources. Regarding I/O, a dual or multiple primary
setup, especially with cluster file systems, will make I/O slower, not
faster, due to distributed locking.

Even if the reason for load balancing is something else, like CPU load,
then I'd probably still just use an NFS or CIFS server on a single
primary rather than a dual primary.

br,
Robert