MongoDB Too many open file while reSync member
Since you have 2TB of data to be resynced, try the following approach.

Follow the below approach for each replica set as required.


Connect to the Primary and back up the database using mongodump, also take the latest document oplog collection.
Shutdown the secondary where you want to resync the data.
Start this secondary as standalone server
Drop the oplog collection in the local database and recreate it by inserting the latest entry from the primary node.
restore the backup data taken from step 1 using mongorestore
Once the restoration is completed, shut down and restart the server as replica set member.