MongoDB Documentation, Release 3.0.4 Collections config Example Internal MongoDB Metadata Chapter 10. Sharding 738 { "_id" : "<hostname>-<timestamp>-<increment>", "server" : "<hostname><:port>", "clientAddr" : "127.0.0.1:63381", "time" : ISODate("2012-12-11T14:09:21.039Z"), "what" : "split", "ns" : "<database>.<collection>", "details" : { "before" : { "min" : { "<database>" : { $minKey : 1 } }, "max" : { "<database>" : { $maxKey : 1 } }, "lastmod" : Timestamp(1000, 0), "lastmodEpoch" : ObjectId("000000000000000000000000") }, "left" : { "min" : { "<database>" : { $minKey : 1 } }, "max" : { "<database>" : "<value>" }, "lastmod" : Timestamp(1000, 1), "lastmodEpoch" : ObjectId(<...>) }, "right" : { "min" : { "<database>" : "<value>" }, "max" : { "<database>" : { $maxKey : 1 } }, "lastmod" : Timestamp(1000, 2), "lastmodEpoch" : ObjectId("<...>") } } } The following example displays a single record of a chunk split from a changelog (page 738) collection: The changelog (page 738) collection stores a document for each change to the metadata of a sharded collec- tion. The config (page 738) database is internal: applications and administrators should not modify or depend upon its content in the course of normal operation. config. changelog