Hi Shantanu
I am not sure the scenario you are describing is the best case. I would
more consider the problem in term of producers and consumers of the data.
Usually is a good practice to put your producer local to your kafka
cluster, so in your case, I would suggest you have producers in the main
and in the backup data center / region.
Then the question arise for your consumers and eventually your data storage
behing. If it is centralized in one place, in could be better to no use
mirror maker and have duplication of the consumer.
So something looking more like a star schema, let me try some ascii art :
Main DC : Data storage/processing DC :
Producer --> Kafka | Consumer ----> Data storage
| /->
Backup DC : | /
Producer --> Kafka | Consumer /
If you have an outage on the main, the backup can "deplace it" (maybe just
with a DNS switch or similar)
If you have an outage on your storage/processing part, messages will just
be stored in kafka the time your consumers are up again (plan enough disk
on kafka to conver your SLA)
Best,
On Fri, May 25, 2018 at 9:00 AM Jörn Franke <jornfra...@gmail.com> wrote:
> Purging will never prevent that it does not get replicated for sure. There
> will be always a case (error to purge etc) and then it is still replicated.
> You may reduce the probability but it will never be impossible.
>
> Your application should be able to handle duplicated messages.
>
> > On 25. May 2018, at 08:54, Shantanu Deshmukh <shantanu...@gmail.com>
> wrote:
> >
> > Hello,
> >
> > We have cross data center replication. Using Kafka mirror maker we are
> > replicating data from our primary cluster to backup cluster. Problem
> arises
> > when we start operating from backup cluster, in case of drill or actual
> > outage. Data gathered at backup cluster needs to be reverse-replicated to
> > primary. To do that I can only think of two options. 1) Use a different
> CG
> > every time for mirror maker 2) Purge topics so that data sent by primary
> > doesn't get replicated back to primary again due to reverse replication.
> >
> > We have opted for purging Kafka topics which are under replication. I use
> > kafka-topics.sh --alter command to set retention of topic to 5 seconds to
> > purge data. But this doesn't see to be a fool proof mechanism. Thread
> > responsible for doing this every minute, and even if it runs it's not
> sure
> > to work as there are multiple conditions. That, segment should be full or
> > certain time should have passed to roll a new segment. It so happened
> > during one such drill to move to backup cluster, purge command was issued
> > and we waited for 5 minutes. Still data wasn't purged. Due to this we
> faced
> > data duplication when reverse replication started.
> >
> > Is there a better way to achieve this?
>
