Field	Description	Example Value	Data Type
hosts	List of MongoDB hosts. Use DNS SRV if srv = true.	x.xxx.xxx.120:27017, x.xxx.xxx.120:27017, x.xxx.xxx.133:27017 (can be multiple)	[]STRING
username/password	Credentials for MongoDB authentication.	"test"/"test"	STRING
authdb	Authentication database (often admin).	"admin"	STRING
replica_set	Name of the replica set, if applicable.	"rs0"	STRING
read_preference	Which node to read from (e.g., secondaryPreferred).	"secondaryPreferred"	STRING
srv	If using DNS SRV connection strings, set to true. When true, there can only be 1 host in hosts field. if true, the hosts key will have a value something like ["mongodatatest.pigiy.mongodb.net"]	true, false	BOOL
database	The MongoDB database name to replicate.	"database_name"	STRING
max_threads	Maximum parallel threads for chunk-based snapshotting.	5	INT
backoff_retry_count	Retries attempt to establish sync again if it fails, increases exponentially ( in minutes - 1, 2,4,8,16... depending upon the backoff_retry_count value)	defaults to 3, takes default value if set to -1	INT
chunking_strategy	The chunking strategy for backfill	timestamp, uses splitVector strategy if the field is left empty. Refer here for more details.

Refer here for more about sync modes.