Summary of Mongo DB Performance measures

1. Have smaller field names
2. Have replica sets and sharding
3. Each document of max size 16 MB .  Document  retrieved in one shot.
4. Eliminate unnecessary indexs
5. compound index over additional indexes
6. Identify & remove obsolete indexes. Indexes that are not used frequently or does not help in search.
7. Slow running queries with explain().
8. XFS file system and RAID 10 or SATA SSD
9. Users should always create indexes to support queries, but should not maintain indexes that queries do not use
10. To understand the effectiveness of the existing indexes being used, an $indexStats aggregation stage can be used to determine how frequently each index is used.
11. The set of data and indexes that are accessed during normal operations is called the working set. It is best practice that the working set fits in RAM.
12. Popular tools such as Chef and Puppet can be used to provision MongoDB instances.
13. MongoDB provides horizontal scale-out for databases using a technique called sharding.MongoDB distributes data across multiple
Replica Sets called shards.
14. Store counts in user profile for faster access than computing on the fly