I have been struggling with the LCS myself. I observed that for the higher level compaction,(from level 4 to 5) it involves much more SSTables than compacting from lower level. One compaction could take an hour or more. By the way, you set the your SSTable size to be 100M?
Thanks. -Wei ________________________________ From: Ивaн Cобoлeв <sobol...@gmail.com> To: user@cassandra.apache.org Sent: Wednesday, February 6, 2013 2:42 AM Subject: Estimating write throughput with LeveledCompactionStrategy Dear Community, Could anyone please give me a hand with understanding what am I missing while trying to model how LeveledCompactionStrategy works: https://docs.google.com/spreadsheet/ccc?key=0AvNacZ0w52BydDQ3N2ZPSks2OHR1dlFmMVV4d1E2eEE#gid=0 Logs mostly contain something like this: INFO [CompactionExecutor:2235] 2013-02-06 02:32:29,758 CompactionTask.java (line 221) Compacted to [chunks-hf-285962-Data.db,chunks-hf-285963-Data.db,chunks-hf-285964-Data.db,chunks-hf-285965-Data.db,chunks-hf-285966-Data.db,chunks-hf-285967-Data.db,chunks-hf-285968-Data.db,chunks-hf-285969-Data.db,chunks-hf-285970-Data.db,chunks-hf-285971-Data.db,chunks-hf-285972-Data.db,chunks-hf-285973-Data.db,chunks-hf-285974-Data.db,chunks-hf-285975-Data.db,chunks-hf-285976-Data.db,chunks-hf-285977-Data.db,chunks-hf-285978-Data.db,chunks-hf-285979-Data.db,chunks-hf-285980-Data.db,]. 2,255,863,073 to 1,908,460,931 (~84% of original) bytes for 36,868 keys at 14.965795MB/s. Time: 121,614ms. Thus spreadsheet is parameterized with throughput being 15Mb and survivor ratio of 0.9. 1) Projected result actually differs from what I observe - what am I missing? 2) Are there any metrics on write throughput with LCS per node anyone could possibly share? Thank you very much in advance, Ivan
