[CASSANDRA-8329] LeveledCompactionStrategy should split large files across data directories when compacting

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.0.12, 2.1.3
• Component/s: Local/Compaction
• Labels: lcs
• Assignee: Marcus Eriksson
• Reporter: J.B. Langston

Authors

Marcus Eriksson

Reviewers

Yuki Morishita

• Tester: Alan Boudreault
• Created: 17/Nov/14 21:43
• Updated: 16/Apr/19 09:31
• Resolved: 24/Nov/14 09:39

Description

Because we fall back to STCS for L0 when LCS gets behind, the sstables in L0 can get quite large during sustained periods of heavy writes. This can result in large imbalances between data volumes when using JBOD support.

Eventually these large files get broken up as L0 sstables are moved up into higher levels; however, because LCS only chooses a single volume on which to write all of the sstables created during a single compaction, the imbalance is persisted.

Issue Links

• relates to: CASSANDRA-7386 JBOD threshold to prevent unbalanced disk utilization