By default, major compactions happen every 7 days. The next major compaction happens 7 days after the last one has finished. This means that the actual time that major compaction happens can impact production processes, which is not ideal if it is desired to run compactions at a specific known off-peak hour, such as at 3 AM.

Cloudera recommends that you disable automatic major compaction by setting the interval to zero in Cloudera Manager (hbase.hregion.majorcompaction = 0). Major compactions should then be run using cron jobs by calling the HBase admin tool.