Logs are quite strange, I have nothing from august 4th to 21th, despite the fact my graylog_7 index has been create 4 days ago:
graylog_7 Contains messages from 4 days ago up to 2 hours ago
Hence, I have nothing for this rotation. Graylog 3.1.0 does not logs anymore in graylog-server.log. In the console log, I have the following, on august 21, when I updated graylog to 3.1, realize I did not have any log in streams and recalculate the ranges:
2019-08-21 16:29:25,891 INFO : org.graylog2.system.jobs.SystemJobManager - Submitted SystemJob <13a21e20-c420-11e9-ba76-0cc47a306f45> [org.graylog2.indexer.ranges.RebuildIndexRangesJob]
2019-08-21 16:29:25,891 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Recalculating index ranges.
2019-08-21 16:29:25,898 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Recalculating index ranges for index set Default index set (graylog_*): 6 indices affected.
2019-08-21 16:29:27,158 INFO : org.graylog2.indexer.ranges.MongoIndexRangeService - Calculated range of [graylog_6] in [1256ms].
2019-08-21 16:29:27,187 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Created ranges for index graylog_6: MongoIndexRange{id=null, indexName=graylog_6, begin=2019-08-04T03:52:00.720Z, end=2019-08-19T19:56:04.740Z, calculatedAt=2019-08-21T14:29:25.901Z, calculationDuration=1256, streamIds=[000000000000000000000001, 5d303decd6816b304090b0c6, 5d30408fd6816b304090b3ba]}
2019-08-21 16:29:28,555 INFO : org.graylog2.indexer.ranges.MongoIndexRangeService - Calculated range of [graylog_4] in [1365ms].
2019-08-21 16:29:28,556 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Created ranges for index graylog_4: MongoIndexRange{id=null, indexName=graylog_4, begin=2019-07-11T17:15:11.600Z, end=2019-07-22T17:55:25.844Z, calculatedAt=2019-08-21T14:29:27.189Z, calculationDuration=1365, streamIds=[000000000000000000000001, 5d039e38d6816b304060586f, 5d303decd6816b304090b0c6, 5d30408fd6816b304090b3ba, 5ce40155d6816b65fe037e36]}
2019-08-21 16:29:29,910 INFO : org.graylog2.indexer.ranges.MongoIndexRangeService - Calculated range of [graylog_3] in [1351ms].
2019-08-21 16:29:29,911 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Created ranges for index graylog_3: MongoIndexRange{id=null, indexName=graylog_3, begin=2019-07-02T07:14:20.792Z, end=2019-07-11T17:15:10.605Z, calculatedAt=2019-08-21T14:29:28.558Z, calculationDuration=1351, streamIds=[000000000000000000000001, 5d039e38d6816b304060586f, 5ce40155d6816b65fe037e36]}
2019-08-21 16:29:31,394 INFO : org.graylog2.indexer.ranges.MongoIndexRangeService - Calculated range of [graylog_5] in [1481ms].
2019-08-21 16:29:31,395 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Created ranges for index graylog_5: MongoIndexRange{id=null, indexName=graylog_5, begin=2019-07-22T17:55:26.298Z, end=2019-08-04T03:51:59.725Z, calculatedAt=2019-08-21T14:29:29.913Z, calculationDuration=1481, streamIds=[000000000000000000000001, 5d303decd6816b304090b0c6, 5d30408fd6816b304090b3ba, 5d4190e5d6816b3040a3778a]}
2019-08-21 16:29:32,780 INFO : org.graylog2.indexer.ranges.MongoIndexRangeService - Calculated range of [graylog_2] in [1383ms].
2019-08-21 16:29:32,781 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Created ranges for index graylog_2: MongoIndexRange{id=null, indexName=graylog_2, begin=1973-04-04T02:50:59.000Z, end=2019-07-02T07:14:19.807Z, calculatedAt=2019-08-21T14:29:31.397Z, calculationDuration=1383, streamIds=[000000000000000000000001, 5d039e38d6816b304060586f, 5ce40155d6816b65fe037e36, 5c112171d6816b11dc00af75]}
2019-08-21 16:29:32,783 INFO : org.graylog2.indexer.ranges.RebuildIndexRangesJob - Done calculating index ranges for 6 indices. Took 6885ms.
2019-08-21 16:29:32,784 INFO : org.graylog2.system.jobs.SystemJobManager - SystemJob <13a21e20-c420-11e9-ba76-0cc47a306f45> [org.graylog2.indexer.ranges.RebuildIndexRangesJob] finished in 6892ms.