Validate can create mongod log files in excess of 500GB (cannot be decompressed by most users) due to log ids 6601200 and 6120300.

See linked examples for cases.

A given validate() output may report 1000 extra/missing index entries, but emit over a million lines to the mongod logs for a single node.
Sample from a 238GB log file where only 755 missing index entries, and 803 extra index entries were reported.

 550312 6601200
 446574 6120300
   2001 22431
    223 20296
    223 20295
    153 20303
    152 9437301
    152 20306
     50 22430
     42 22943
     41 22944
     21 51773
     11 20300

Ideally validate only reports these logs once. It's unclear if validate() output is reporting all the index inconsistencies present or if this is just extra noise.