Major - P3 Seems to start happening after we switched WT as default storage engine. Tests timed out waiting for slave to replicate. Logs suggests that slaves are not even trying:
m31000| 2015-05-29T08:01:19.585-0400 I NETWORK [initandlisten] connection accepted from 127.0.0.1:44323 #1 (1 connection now open)
m31000| 2015-05-29T08:01:19.601-0400 I ACCESS [conn1] Successfully authenticated as principal __system on local
m31001| 2015-05-29T08:01:20.388-0400 I REPL [replslave] syncing from host:127.0.0.1:31000
m31000| 2015-05-29T08:01:20.388-0400 I NETWORK [initandlisten] connection accepted from 127.0.0.1:44324 #2 (2 connections now open)
m31000| 2015-05-29T08:01:20.413-0400 I ACCESS [conn2] Successfully authenticated as principal __system on local
m31001| 2015-05-29T08:01:20.414-0400 I REPL [replslave] nextOpTime May 29 08:01:19 5568550f:1 > syncedTo May 29 08:01:08 55685504:a
m31001| time diff: 11sec
m31001| tailing: 0
m31001| data too stale, halting replication
m31001| 2015-05-29T08:01:20.414-0400 I REPL [replslave] caught SyncException
m31001| 2015-05-29T08:01:20.414-0400 I REPL [replslave] sleep 10 sec before next pass
:30 +0000
m31001| 2015-05-29T08:01:30.415-0400 I REPL [replslave] all sources dead: data too stale halted replication, sleeping for 5 seconds
m31000| 2015-05-29T08:01:30.415-0400 I NETWORK [conn2] end connection 127.0.0.1:44324 (1 connection now open)
:35 +0000
m31001| 2015-05-29T08:01:35.415-0400 I REPL [replslave] all sources dead: data too stale halted replication, sleeping for 5 seconds
:40 +0000
m31001| 2015-05-29T08:01:40.415-0400 I REPL [replslave] all sources dead: data too stale halted replication, sleeping for 5 seconds
:45 +0000
m31001| 2015-05-29T08:01:45.416-0400 I REPL [replslave] all sources dead: data too stale halted replication, sleeping for 5 seconds
:49 +0000
assert.soon failed, msg:expected count: 1020 from : connection to 127.0.0.1:31001
Error: assert.soon failed, msg:expected count: 1020 from : connection to 127.0.0.1:31001
at Error (<anonymous>)
at doassert (src/mongo/shell/assert.js:11:14)
at Function.assert.soon (src/mongo/shell/assert.js:189:13)
at soonCount (jstests/repl/repl6.js:6:12)
at doTest (jstests/repl/repl6.js:63:5)
at jstests/repl/repl6.js:77:1
2015-05-29T08:01:49.760-0400 E QUERY [thread1] Error: assert.soon failed, msg:expected count: 1020 from : connection to 127.0.0.1:31001
at Error (<anonymous>)
at doassert (src/mongo/shell/assert.js:11:14)
at Function.assert.soon (src/mongo/shell/assert.js:189:13)
at soonCount (jstests/repl/repl6.js:6:12)
at doTest (jstests/repl/repl6.js:63:5)
at jstests/repl/repl6.js:77:1 at src/mongo/shell/assert.js:13
failed to load: jstests/repl/repl6.js