Oracle alert.log "Thread 1 cannot allocate new log" on AWS RDS

I migrated from an on-premise Oracle XE to Amazon RDS. It's running on a T3.medium server with gp3 storage (200 GB/12000 IOPS). Almost every fifth minute the alert.log says like this: "Thread 1 cannot allocate new log, sequence 10209 Checkpoint not complete" 3-4 seconds after that it logs another message: "Thread 1 advanced to log sequence 10209 (LGWR switch), current SCN: 472780758" And immediately after that: "ARC1 (PID:6427): Archived Log entry 10205 added for B-1189761742.T-1.S-10208 ID 0x7efecf3c1c4d LAD:1 [krse.c:4934]" Like this: Reading about the first message ("cannot allocate new log") it seems as a "bad" message. The typical advice is to increase the redo log file size. So I added 4 log files, each 512 Mb. The advice was to remove the old log (128 Mb each) files but they are almost always "ACTIVE" so I have just managed to remove 1. This is the current status: ... and I still get the error message in alert.log. The parameter archive_lag_target is set to 300 (5 minutes), so I guess that's why it switches log file every five minutes. (I don't think I can change that setting in RDS.) Looking at the disk operations in AWS doesn't imply that the disk is under too heavy load: Should i be worried about the message "Thread 1 cannot allocate new log..."? If yes: what can be the reason for it and what can I do about it? **Update:** When I issued a manual checkpoint using: EXEC rdsadmin.rdsadmin_util.checkpoint; ... it did a checkpoint in less than a second and all but one log file became INACTIVE. It seems as if it doesn't do automatic checkpoints.