How many requests can mongodb handle before sharding is necessary?

Question

Does anybody know (from personal experience or official documentation) how many concurrent requests can a single MongoDb server handle before sharding is advised?

Answer 1

If your working set exceeds the RAM you can afford for a single server, or your disk I/O requirements exceed what you can provide on a single server, or (less likely) your CPU requirements exceed what you can get on one server, then you'll need to shard. All these depend tremendously on your specific workload. See http://docs.mongodb.org/manual/faq/storage/#what-is-the-working-set