Hi
We have a 6 node cluster in two DCs, Cassandra version 1.1.11, RF=3 in each DC. The DataStax Documentation says the following: Initiate a major compaction through nodetool compact<http://www.datastax.co= m/docs/1.1/references/nodetool#nodetool-compact<http://www.datastax.co=%20m/docs/1.1/references/nodetool#nodetool-compact>>. A major compaction merges all SSTables into one. Though major compaction can free disk space used by accumulated SSTables, during runtime it temporarily doubles disk space usage and is I/O and CPU intensive. After running a major compaction, automatic minor compactions are no longer triggered on a frequent basis. Consequently, you no longer have to manually run major compactions on a routine basis. Expect read performance to improve immediately following a major compaction, and then to continually degrade until you invoke the next major compaction. For this reason, DataStax does not recommend major compaction. A maintenance procedure has been run ( periodically ) on the nodes in the cluster which performs repair -pr, flush, compact, then cleanup. This runs fine for all CFs except one which is very large, with large rows. The entries all have TTLs specified which are less than gc_grace. Currently the SSTables are as follows for the xxxx CF, the maintenance just completed after running for 9+ hours: 19977911 Dec 27 06:38 xxxx-hf-57288-Data.db 5817 Dec 27 06:52 xxxx-hf-57304-Data.db 2735747237 Dec 27 06:52 xxxx-hf-57291-Data.db 718192 Dec 27 06:52 xxxx-hf-57305-Data.db 2581373226 Dec 29 16:48 xxxx-hf-57912-Data.db 936062446 Jan 9 22:22 xxxx-hf-58875-Data.db 235463043 Jan 10 05:23 xxxx-hf-58888-Data.db 60851675 Jan 10 08:33 xxxx-hf-58893-Data.db 60871570 Jan 10 11:44 xxxx-hf-58898-Data.db 60537384 Jan 10 14:54 xxxx-hf-58903-Data.db Min_compaction_threshold is set to 4. Now for the questions: 1) Given that the DataStax recommendation was not followed - will minor compactions still be triggered if the major compactions are no longer performed? 2) Would the maintenance steps: repair -pr, flush, and cleanup still be useful? Thanks
