CXX-479 Backport server r2.6.7..r2.6.9 changes

Server SHAs picked into this commit:

2d45919
1b64aa8
78d52ff
1dd33f4
224067d
8f1c734
91ab64a
a5408ed
738e366
5b0ff61
3abc04d
a34e139
77fb852
b6a66a0
9af0d09
a5a4852
e9e813d
e3a7692
3133d04
2dee1ad
df313bc