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Dikang Gu commented on CASSANDRA-11550: --------------------------------------- [~krummas] I got some time to test it in one of our cluster, I think the result looks promising, after I change the fanout size from 10 to 6, I see ~40% drop of the original data size, and the disk io dropped as well. Take one node for example, before the change, the levels look like this: SSTables in each level: [0, 12/10, 112/100, 98, 0, 0, 0, 0, 0] SSTables in each level: [1, 11/10, 114/100, 99, 0, 0, 0, 0, 0] After I change the fanout size to 6, it becomes: SSTables in each level: [0, 6, 41/36, 120, 0, 0, 0, 0, 0] SSTables in each level: [0, 6, 39/36, 123, 0, 0, 0, 0, 0] which is more efficient, in terms of space amplification and write amplification. [~krummas] what do you think? Thanks! > Make the fanout size for LeveledCompactionStrategy to be configurable > --------------------------------------------------------------------- > > Key: CASSANDRA-11550 > URL: https://issues.apache.org/jira/browse/CASSANDRA-11550 > Project: Cassandra > Issue Type: New Feature > Components: Compaction > Reporter: Dikang Gu > Assignee: Dikang Gu > Labels: lcs > Fix For: 3.x > > Attachments: > 0001-make-fanout-size-for-leveledcompactionstrategy-to-be.patch > > > Currently, the fanout size for LeveledCompactionStrategy is hard coded in the > system (10). It would be useful to make the fanout size to be tunable, so > that we can change it according to different use cases. > Further more, we can change the size dynamically. -- This message was sent by Atlassian JIRA (v6.3.4#6332)