I don't know what exactly compaction logs is like in system.log. But I see logs like this in system.log, I think maybe this is the compaction log
INFO [ScheduledTasks:1] 2016-01-09 22:51:02,664 StatusLogger.java (line 118) ColumnFamily Memtable ops,data INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.schema_triggers 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.local 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.peers 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.batchlog 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.NodeIdInfo 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.compactions_in_progress 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.schema_keyspaces 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.compaction_history 9,2650 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.paxos 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,670 StatusLogger.java (line 121) system.schema_columns 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,671 StatusLogger.java (line 121) system.schema_columnfamilies 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,671 StatusLogger.java (line 121) system.IndexInfo 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,671 StatusLogger.java (line 121) system.range_xfers 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,671 StatusLogger.java (line 121) system.peer_events 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,671 StatusLogger.java (line 121) system.hints 0,0 INFO [ScheduledTasks:1] 2016-01-09 22:51:02,671 StatusLogger.java (line 121) system.sstable_activity 69,20930 ... To clarify the source of compaction, I restarted the cluster and truncate system.hints at Jan 8. However, it also shows compactionhistory of hints like this. I checked the timestamp however, many history items are compared at Jan 6. -b313-11e5-a211-45b7aa88107c system hints 1451933296208 14472833 14276596 {1:2} 7a7e5ad0-b42c-11e5-a211-45b7aa88107c system sstable_activity 1452053883133 3215 852 {4:23} 16e97320-b264-11e5-a211-45b7aa88107c system sstable_activity 1451857865554 3114 726 {4:23} f8ab7d40-b62d-11e5-aa30-45b7aa88107c system sstable_activity 1452274426644 3047 751 {4:23} ea955a00-b173-11e5-a211-45b7aa88107c system hints 1451754711968 18970740 18970740 {1:1} cf98c3c0-b54e-11e5-bce5-45b7aa88107c system sstable_activity 1452178579964 3503 964 {4:23} 9e74bf80-b4c0-11e5-ac1a-45b7aa88107c system sstable_activity 1452117508984 3135 800 {4:22} 4b9ffb20-b27d-11e5-a211-45b7aa88107c system sstable_activity 1451868691410 3037 791 {4:23} 4f059400-b3e0-11e5-a211-45b7aa88107c system sstable_activity 1452021168448 2985 802 {1:2, 4:23} 9de3b670-b439-11e5-ac1a-45b7aa88107c system hints 1452059525975 10532201 10550449 {2:2} f1c2f710-b439-11e5-ac1a-45b7aa88107c system hints 1452059666689 10479415 10479415 {1:1} 9b4f7700-b439-11e5-ac1a-45b7aa88107c system hints 1452059521648 10594437 10532000 {1:1, 2:1} 402f42d0-b2fc-11e5-a211-45b7aa88107c system sstable_activity 1451923218301 3184 776 {4:23} 47589f00-b231-11e5-a211-45b7aa88107c system sstable_activity 1451836042480 3212 785 {4:23} 848ee140-b439-11e5-ac1a-45b7aa88107c system hints 1452059483476 10648367 10601270 {1:1, 2:1} 8736f390-b4f9-11e5-ac1a-45b7aa88107c system hints 1452141951305 8261575 8112577 {1:1} ff591b80-b37a-11e5-a211-45b7aa88107c system sstable_activity 1451977655608 3025 765 {4:23} Besides, there are also lots pending compaction tasks over 70000000. On Sat, Jan 9, 2016 at 2:42 AM, Robert Coli <rc...@eventbrite.com> wrote: > > > On Thu, Jan 7, 2016 at 6:30 PM, Shuo Chen <chenatu2...@gmail.com> wrote:, >> >> I am using Cassandra 2.0.16 with 4 nodes and found too many compactions >> for this cluster. This caused too much full gc and choked the system. I >> have discussed the high gc in previous mails but didnot get the satisfied >> answers. >> >> To clarify the source of the compactions, I shutdown all the clients and >> there is no reading and writing requests outside. Besides, >> hinted_handoff_enabled: false is set. The cluster is restarted yesterday >> and have run for 1.5 days. >> > > Do you see compactions of the hints CF in the system.log? > > =Rob > > -- *陈硕* *Shuo Chen* chenatu2...@gmail.com chens...@whaty.com