Hashed _id's aren't the bottleneck. Disks are the bottleneck. MongoDB is seriously lacking in the compression department and bogs down our disks constantly. Ri

Hashed _id's aren't the bottleneck. Disks are the bottleneck. MongoDB is seriously lacking in the compression department and bogs down our disks constantly. Riak is not slow as long as you're not running your cluster on VPSs. At our scale Riak's performance has been significantly better than MongoDB's due to our heavy write load, and there are fewer issues with using big disks with somewhat larger seek times.