Hi David,
What tool(s) are you using to create new topics? Is it the kafka-topics.sh
that ships with Apache Kafka?
Cheers,
Liam Clarke-Hutchinson
On Wed, Nov 10, 2021 at 11:41 AM David Ballano Fernandez <
dfernan...@demonware.net> wrote:
> Hi All,
> Trying to figure out why my brokers have some disk imbalance I have found
> that Kafka (maybe this is the way it is supposed to work?) is not spreading
> all replicas to all available brokers.
>
> I have been trying to figure out how a topic with 5 partitions with
> replication_factor=3 (15 replicas) could endup having all replicas spread
> over 9 brokers instead of 15, especially when there are more brokers than
> the total replicas for that specific topic.
>
> cluster has 48 brokers.
>
> # topics.py describe -topic topic1
> {145: 1, 148: 2, *101: 3*, 146: 1, 102: 2, 147: 1, 103: 2, 104: 2, 105: 1}
> the keys are the brokerid and the values is how many replicas they have.
>
> As you can see brokerid 101 has 3 replicas. which make the disk unbalanced
> compared to other brokers.
>
> I created a brand new topic in a test cluster with 24 brokers. topic has 5
> partitions with replication factor 3
> topics.py describe -topic test
> {119: 1, 103: 1, 106: 2, 109: 1, 101: 2, 114: 1, 116: 2, 118: 1, 111: 2,
> 104: 1, 121: 1}
>
> This time kafka decided to spread the replicas over 11 brokers instead of
> 15.
> just for fun i ran a partition reassignment for topic test, spreading all
> replicas to all brokers, result:
>
> # topics.py describe -topic test
> {110: 1, 111: 1, 109: 1, 108: 1, 112: 1, 103: 1, 107: 1, 105: 1, 104: 1,
> 106: 1, 102: 1, 118: 1, 116: 1, 113: 1, 117: 1}
>
> Now all replicas are spread across 15 brokers.
>
> Is there something I am missing? Maybe the reason is to keep network
> chatter down?. By the way, I don't have any rack awareness configured.
> Thanks!
>
