MongoDB 1.6 Released



MongoDB 1.6.0 is the fourth stable major release (even numbers are “stable” : 1.0, 1.2, 1.4, …) and is the culmination of the 1.5 development series.


The focus of the 1.6 release is scale-out.  Sharding is now production-ready.  The combination of sharding and replica sets allows one to build out horizontally scalable data storage clusters with no single points of failure.

A single instance of mongod can be upgraded to a distributed cluster with zero downtime when the need arises.

A big thanks to all the 1.5.x beta testers of sharding (including foursquare and who have been using sharding in production for a while now).

Replica Sets 

Replica sets allow you to setup a high availability cluster with automatic fail over and recovery.  Replica pair users should, when convenient, migrate to replica sets.

Other Improvements in v1.6

  • acknowledged replication: The w option (and wtimeout) force writes to be propagated to N servers before returning success (works well with replica sets).
  • $or queries
  • Up to 64 indexes/collection
  • Improved concurrency
  • $slice operator
  • Support for UNIX domain sockets and IPv6
  • Windows service improvements
  • The C++ client is a separate tarball from the binaries


Release Notes:

Full change log

Please report any issues to (support forums) or (bug/feature db).

What’s Next

Now that 1.6 is out, we’re going to be focusing on 1.8.  Help us prioritize features for this release by voting for your key needs at  The #1 feature queued for v1.8 is single server durability.

More Information

Please join 10gen CEO and Co-Founder Dwight Merriman for the webinar What’s New in MongoDB v1.6 on Tuesday, August 10 at 12:30pm ET / 9:30am PT.