[389-users] Re: Complex MMR scenarios
On 1 Oct 2020, at 20:27, Eugen Lamers
<eugen.lamers(a)br-automation.com> wrote:
Hi,
we want to setup a Multi Master Replication that represents a scenario with several
mobile environments which need to replicate with some immobile server from time to time.
Is it possible - and reasonable - to group the servers of a mobile environment together to
a kind of sub-level MMR which replicates with the higher level MMR of the immobile
environment. This replication between the different "levels" would be triggered
somehow externally, because there would not always be a (sufficient) connection between
them.
This would represent some kind of combination of MMR and cascading replication. Is there
someone with experience with such kind of scenarios?
I haven't heard of such a scenario but I'd ask "what are you trying to
achieve" rather than commenting on the design too much.
An early issue you will hit is that replication is *push* based, so the
"immobile" servers need to be continually updated to know where the
"mobile" server is in order to know how to contact it. It's not
"pull" based where the moving server could always access the static server.
Additionally, because it's "push" based, the sending server sets the
schedule of when to replicate. Certainly, there is a window of validity where a server can
be "caugh up" (the changelog max age parameter is how long a server can be
disconnected and still replicated to later to "update" it). Again, if this were
"pull" based, the mobile server could "choose" when to recieve
it's update.
But saying this, I think you have a problem space in mind, and while this may be a
solution, knowing more about the challenge you want to solve may help us give better
advice about how to configure your topology and potentially the integrating applications.
Thanks,
—
Sincerely,
William Brown
Senior Software Engineer, 389 Directory Server
SUSE Labs, Australia