RDSLowDiskSpaceCount #

Meaning #

Alert is triggered when at least one RDS instance is under the threshold on storage left.

Impact #

The PostgreSQL instance(s) might stop to prevent data corruption if no more disk space is available.

Diagnosis #

1. Find affected instance list in prometheus with:

   max by (aws_account_id, aws_region, dbidentifier) (rds_free_storage_bytes{} * 100 / rds_allocated_storage_bytes{}) < 20
   

2. Refer to RDSDiskSpaceLimit for each of them as it’s the same alert just ringing a bit earlier.