Recent tools Evergreen tests have started showing a failure in the mongofiles_write_concern_mongos.js test when run against a 3.7 nightly. Nothing relating to mongofiles changed in the tools during the time the failures started and the tests pass when run against MongoDB 3.6.
- Failing test (against server v3.7.9-154-g51dce76):
- Passing test (against server v3.7.3-468-gb299eab):
The test case has 2 nodes of a 3-node shard down, but mongofiles is run with w:1,wtimeout:10000. In the failing case, mongofiles hangs waiting for a database response. Eventually, after several hours, the process is terminated.
Note: The mongofiles log output is deceptive, it claims the file is added, but the hang occurs during a deferred close() call when mgo is trying to flush all data to the database and ensure indexes exist.