The write-concern number is the value of “w” which maps to the number of replicas that the write must propagate to before being considered successful when w > 1.
WriteConcern control the write behavior for with various options, as well as exception raising on error conditions.
- -1 = don’t even report network errors
- 0 = default, don’t call getLastError by default
- 1 = basic, call getLastError, but don’t wait for slaves
- 2+= wait for slaves
wtimeout how long to wait for slaves before failing
- 0 = indefinite
- > 0 = ms to wait
fsync force fsync to disk