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Posted to dev@kafka.apache.org by Alexandre Dupriez <al...@gmail.com> on 2019/08/13 08:17:18 UTC
UnderReplicatedPartitions = 0 and UnderMinPartitionIsrCount > 0
Hello all,
We run into a scenario where we had misconfigured the replication factor
and the minimum in-sync replicas count in such a way that the replication
factor (either default or defined at the topic level) is strictly lower
than the property min.insync.replicas.
We observed broker metrics reporting UnderReplicatedPartitions = 0 and
UnderMinPartitionIsrCount > 0, and the topic’s partitions were unavailable
for producers (with ack=all) and consumers.
Since it seems to be impossible in this scenario to ever reach the number
of in-sync replicas, making partitions permanently unavailable, it could be
worth to prevent this misconfiguration to make its way to the broker, e.g.
a check could be added when a topic is created to ensure the replication
factor is greater than or equals to the minimum number of in-sync replicas.
I may have missed something though. What do you think?
Thank you,
Alexandre
Re: UnderReplicatedPartitions = 0 and UnderMinPartitionIsrCount > 0
Posted by Alexandre Dupriez <al...@gmail.com>.
Hello James,
Many thanks for your quick response and pointing out the associated JIRA.
Happy to dig a bit on the function paths affected by a consistency check on
these parameters, as explained in the ticket, and see what could be done
(or not).
Thanks,
Alexandre
Le mer. 14 août 2019 à 06:11, James Cheng <wu...@gmail.com> a écrit :
> Alexandre,
>
> You are right that this is a problem. There is a JIRA on this from a while
> back.
>
> https://issues.apache.org/jira/plugins/servlet/mobile#issue/KAFKA-4680
>
> I don’t think anyone is currently working on it right now.
>
> -James
>
> Sent from my iPhone
>
> > On Aug 13, 2019, at 1:17 AM, Alexandre Dupriez <
> alexandre.dupriez@gmail.com> wrote:
> >
> > Hello all,
> >
> > We run into a scenario where we had misconfigured the replication factor
> > and the minimum in-sync replicas count in such a way that the replication
> > factor (either default or defined at the topic level) is strictly lower
> > than the property min.insync.replicas.
> >
> > We observed broker metrics reporting UnderReplicatedPartitions = 0 and
> > UnderMinPartitionIsrCount > 0, and the topic’s partitions were
> unavailable
> > for producers (with ack=all) and consumers.
> >
> > Since it seems to be impossible in this scenario to ever reach the number
> > of in-sync replicas, making partitions permanently unavailable, it could
> be
> > worth to prevent this misconfiguration to make its way to the broker,
> e.g.
> > a check could be added when a topic is created to ensure the replication
> > factor is greater than or equals to the minimum number of in-sync
> replicas.
> >
> > I may have missed something though. What do you think?
> >
> > Thank you,
> > Alexandre
>
Re: UnderReplicatedPartitions = 0 and UnderMinPartitionIsrCount > 0
Posted by James Cheng <wu...@gmail.com>.
Alexandre,
You are right that this is a problem. There is a JIRA on this from a while back.
https://issues.apache.org/jira/plugins/servlet/mobile#issue/KAFKA-4680
I don’t think anyone is currently working on it right now.
-James
Sent from my iPhone
> On Aug 13, 2019, at 1:17 AM, Alexandre Dupriez <al...@gmail.com> wrote:
>
> Hello all,
>
> We run into a scenario where we had misconfigured the replication factor
> and the minimum in-sync replicas count in such a way that the replication
> factor (either default or defined at the topic level) is strictly lower
> than the property min.insync.replicas.
>
> We observed broker metrics reporting UnderReplicatedPartitions = 0 and
> UnderMinPartitionIsrCount > 0, and the topic’s partitions were unavailable
> for producers (with ack=all) and consumers.
>
> Since it seems to be impossible in this scenario to ever reach the number
> of in-sync replicas, making partitions permanently unavailable, it could be
> worth to prevent this misconfiguration to make its way to the broker, e.g.
> a check could be added when a topic is created to ensure the replication
> factor is greater than or equals to the minimum number of in-sync replicas.
>
> I may have missed something though. What do you think?
>
> Thank you,
> Alexandre