You can view records of operations in the last 30 days on the Operation Logs page in the Anti-DDoS Pro console.

Note Operation logs only record important operations in the last 30 days.
Recorded operation Supported
Changes of ECS instance IP addresses Yes
Deactivation of black holes Yes
Blocking or unblocking traffic Yes
Changes of scrubbing mode of Layer-4 traffic Yes
Changes of HTTP flood protection modes Yes
Changes of the burstable protection bandwidth Yes