Events Supported by Event Monitoring

**Table 1** Document Database Service (DDS)
Event Source	Event Name	Event ID	Event Severity	Description	Solution	Impact
DDS	DB instance creation failure	DDSCreateInstanceFailed	Major	A DDS instance fails to be created due to insufficient disks, quotas, and underlying resources.	Check the number and quota of disks. Release resources and create DDS instances again.	DDS instances cannot be created.
	Replication failed	DDSAbnormalReplicationStatus	Major	The possible causes are as follows: The replication delay between the primary and secondary nodes is too long, which usually occurs when a large amount of data is written to databases or a large transaction is performed. During off-peak hours, the replication delay gradually decreases. The network between the primary and secondary nodes is disconnected.	Submit a service ticket.	Your applications are not affected because this event does not interrupt data read and write.
	Replication recovered	DDSReplicationStatusRecovered	Major	The replication delay between the primary and standby instances is within the normal range, or the network connection between them has restored.	No further action is required.	None
	DB instance faulty	DDSFaultyDBInstance	Major	This event is a key alarm event and is reported when an instance is faulty due to a disaster or a server failure.	Submit a service ticket.	The database service may be unavailable.
	DB instance recovered	DDSDBInstanceRecovered	Major	If a disaster occurs, NoSQL provides an HA tool to automatically or manually rectify the fault. After the fault is rectified, this event is reported.	No further action is required.	None
	Faulty node	DDSFaultyDBNode	Major	This event is a key alarm event and is reported when a database node is faulty due to a disaster or a server failure.	Check whether the database service is available and submit a service ticket.	The database service may be unavailable.
	Node recovered	DDSDBNodeRecovered	Major	If a disaster occurs, NoSQL provides an HA tool to automatically or manually rectify the fault. After the fault is rectified, this event is reported.	No further action is required.	None
	Primary/standby switchover or failover	DDSPrimaryStandbySwitched	Major	This event is reported when a primary/secondary switchover or a failover is triggered.	No further action is required.	None
	Insufficient storage space	DDSRiskyDataDiskUsage	Major	The storage space is insufficient.	Scale up storage space. For details, see section "Scaling Up Storage Space" in the corresponding user guide.	The instance is set to read-only and data cannot be written to the instance.
	Data disk expanded and being writable	DDSDataDiskUsageRecovered	Major	The capacity of a data disk has been expanded and the data disk becomes writable.	No action is required.	No adverse impact.