Known issues and limitations¶

This page lists known limitations for using Percona Link for MongoDB

Versions and topology¶

Sharded clusters are not supported
MongoDB versions that reached End-of-Life are not supported
PLM connects only to the primary node in the replica set. You cannot force connection to secondary members using the directConnection option. This option is ignored.

Queryable encryption is not supported
Users and roles are not synchronized
Timeseries collections are not supported
system.* collections are not replicated
Clustered collections with indexes that have the expireAfterSeconds field defined are not supported because the change stream does not provide a Time-to-Live (TTL) value for the index
Capped collections created or converted as the result of cloneCollectionAsCapped and convertToCapped commands are not supported. These operations don’t change the event and are not captured by the change streams.
Percona Memory Engine is not supported
Persistent Query Settings (added in MongoDB 8) are not supported
documents that have field names with periods and dollar signs are not supported

The following functionalities are not supported:

Multiple source or multiple target clusters
You cannot resume initial synchronization if an issue occurred. You must start it from scratch.
Database upgrade during the sync, even in the paused state.
Reverse synchronization
External authentication via Kerberos, AWS and LDAP
GridFS

Last update: September 8, 2025
Created: September 8, 2025