Yup, we set it to 100M. Currently we have around 1Tb of data per node(getting to level 5 now) + data pieces are rather large(small tables would flush more often).
Yes, you're right, it's slower thus building mental models is more time effective than experimenting :) Ivan 2013/2/6 Wei Zhu <wz1...@yahoo.com>: > 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 > >
