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haiyangyu edited comment on KAFKA-7690 at 11/30/18 7:58 AM: ------------------------------------------------------------ [~omkreddy] [~ijuma] [~guozhang] [~hachikuji] [~cmccabe] [~junrao] was (Author: yuhaiyang): [~omkreddy] [~ijuma] [~guozhang] [~hachikuji] [~cmccabe] [~junrao] > Change disk allocation policy for multiple partitions on a broker when topic > is created > --------------------------------------------------------------------------------------- > > Key: KAFKA-7690 > URL: https://issues.apache.org/jira/browse/KAFKA-7690 > Project: Kafka > Issue Type: Improvement > Affects Versions: 0.10.2.0, 1.0.0, 2.0.0 > Reporter: haiyangyu > Priority: Major > > h3. *Background* > if target topic partitions lager than broker size when create a topic or add > partition, one broker will be assigned more than one partition. if current > all disk is not balance, such as one disk has one partition and the other one > has four partitions due to topic delete or others, the mutil partitions will > be all allocated in the first disk, and if the target topic has a large flow, > it is easily to fill up the disk io. > h3. *Improvement strategy* > when mutil ** partition is going to be allocated on a broker, the strategy is > as follow: > 1、calculate the target topic partition count and total partition count on > each disk. > topic count > 2、sorted by the target topic partition count wich ascending order, if the > target topic partition count is equal, sorted by the total partitions on each > disk. > h3. *Example* > > ||disk||target topic partition count||total partition count|| > |disk1|0|11| > |disk2|0|9| > when tow partitions are assigned on this broker, if use origin strategy, the > result is as follows: > ||disk||target topic partition count||total partition count|| > |disk1|0|11| > |disk2|2|11| > use new strategy, the result is as follows: > ||disk||target topic partition count||total partition count|| > |disk1|1|12| > |disk2|1|10| > if the topic has a huge flow such as 50MB/s per partition, it is easily to > fill up disk2 io if use origin strategy. However if use new strategy, it's > well in disk io rebalance. > h3. *Summary* > This strategy is good to build a big cluster and create a topic which has > huge amount partition, the disk io will be more balanced. > -- This message was sent by Atlassian JIRA (v7.6.3#76005)