Any input from anyone, please?
It's another thing that seems to be rather poorly documented: it's unclear
what to expect, what 'normal' behavior should be, and what can be done
about the huge amount of writes by monitors.
/Z
On Mon, 9 Oct 2023 at 12:40, Zakhar Kirpichenko <zakhar@xxxxxxxxx> wrote:
> Hi,
>
> Monitors in our 16.2.14 cluster appear to quite often run "manual
> compaction" tasks:
>
> debug 2023-10-09T09:30:53.888+0000 7f48a329a700 4 rocksdb: EVENT_LOG_v1
> {"time_micros": 1696843853892760, "job": 64225, "event": "flush_started",
> "num_memtables": 1, "num_entries": 715, "num_deletes": 251,
> "total_data_size": 3870352, "memory_usage": 3886744, "flush_reason":
> "Manual Compaction"}
> debug 2023-10-09T09:30:53.904+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:30:53.908+0000 7f48a3a9b700 4 rocksdb: (Original Log
> Time 2023/10/09-09:30:53.910204) [db_impl/db_impl_compaction_flush.cc:2516]
> [default] Manual compaction from level-0 to level-5 from 'paxos .. 'paxos;
> will stop at (end)
> debug 2023-10-09T09:30:53.908+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:30:53.908+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:30:53.908+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:30:53.908+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:30:53.908+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:30:53.908+0000 7f48a3a9b700 4 rocksdb: (Original Log
> Time 2023/10/09-09:30:53.911004) [db_impl/db_impl_compaction_flush.cc:2516]
> [default] Manual compaction from level-5 to level-6 from 'paxos .. 'paxos;
> will stop at (end)
> debug 2023-10-09T09:32:08.956+0000 7f48a329a700 4 rocksdb: EVENT_LOG_v1
> {"time_micros": 1696843928961390, "job": 64228, "event": "flush_started",
> "num_memtables": 1, "num_entries": 1580, "num_deletes": 502,
> "total_data_size": 8404605, "memory_usage": 8465840, "flush_reason":
> "Manual Compaction"}
> debug 2023-10-09T09:32:08.972+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:08.976+0000 7f48a3a9b700 4 rocksdb: (Original Log
> Time 2023/10/09-09:32:08.977739) [db_impl/db_impl_compaction_flush.cc:2516]
> [default] Manual compaction from level-0 to level-5 from 'logm .. 'logm;
> will stop at (end)
> debug 2023-10-09T09:32:08.976+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:08.976+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:08.976+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:08.976+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:08.976+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:08.976+0000 7f48a3a9b700 4 rocksdb: (Original Log
> Time 2023/10/09-09:32:08.978512) [db_impl/db_impl_compaction_flush.cc:2516]
> [default] Manual compaction from level-5 to level-6 from 'logm .. 'logm;
> will stop at (end)
> debug 2023-10-09T09:32:12.764+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:12.764+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:12.764+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:12.764+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:12.764+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:32:12.764+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.028+0000 7f48a329a700 4 rocksdb: EVENT_LOG_v1
> {"time_micros": 1696844009033151, "job": 64231, "event": "flush_started",
> "num_memtables": 1, "num_entries": 1430, "num_deletes": 251,
> "total_data_size": 8975535, "memory_usage": 9035920, "flush_reason":
> "Manual Compaction"}
> debug 2023-10-09T09:33:29.044+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.048+0000 7f48a3a9b700 4 rocksdb: (Original Log
> Time 2023/10/09-09:33:29.049585) [db_impl/db_impl_compaction_flush.cc:2516]
> [default] Manual compaction from level-0 to level-5 from 'paxos .. 'paxos;
> will stop at (end)
> debug 2023-10-09T09:33:29.048+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.048+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.048+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.048+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.048+0000 7f4899286700 4 rocksdb:
> [db_impl/db_impl_compaction_flush.cc:1443] [default] Manual compaction
> starting
> debug 2023-10-09T09:33:29.048+0000 7f48a3a9b700 4 rocksdb: (Original Log
> Time 2023/10/09-09:33:29.050355) [db_impl/db_impl_compaction_flush.cc:2516]
> [default] Manual compaction from level-5 to level-6 from 'paxos .. 'paxos;
> will stop at (end)
>
> I have removed a lot of interim log messages to save space.
>
> During each compaction the monitor process writes approximately 500-600 MB
> of data to disk over a short period of time. These writes add up to tens of
> gigabytes per hour and hundreds of gigabytes per day.
>
> Monitor rocksdb and compaction options are default:
>
> "mon_compact_on_bootstrap": "false",
> "mon_compact_on_start": "false",
> "mon_compact_on_trim": "true",
> "mon_rocksdb_options":
> "write_buffer_size=33554432,compression=kNoCompression,level_compaction_dynamic_level_bytes=true",
>
> Is this expected behavior? Is this something I can adjust in order to
> extend the system storage life?
>
> Best regards,
> Zakhar
>
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