Cloud Monitor will change the statistical method for metrics of Classic Load Balancer (CLB), formerly known as Server Load Balancer (SLB), from 10:00:00 to 23:00:00 on March 25, 2024. After the statistical method for CLB metrics is changed, the statistical values are also changed, and alerts may be triggered accordingly.
The statistical values of Layer 7 metrics InstanceRt and InstanceUpstreamRt for CLB are increased or decreased due to the change in the statistical method. The statistical method for the metrics is changed from calculating the average of values from multiple listener ports to calculating the weighted average based on the access queries per second (QPS) of the listener ports. The following examples show the calculation process:
Example 1: The new statistical method results in a larger statistical value, compared with the old statistical method.
Statistical dimension
Listener 1
Listener 2
Port number
8080
443
QPS
3
354
Response time (ms)
0
38
Old statistical method
(0 + 38)/2 = 19
New statistical method
(0 × 3)/(3 + 354) + (38 × 354)/(3 + 354) = 37.68
Example 2: The statistical values calculated by using both the new and the old statistical methods do not fluctuate significantly.
Statistical dimension
Listener 1
Listener 2
Port number
8080
443
QPS
2
5
Response time (ms)
44
49.2
Old statistical method
(44 + 49.2)/2 = 46.6
New statistical method
(44 × 2)/(2 + 5) + (49.2 × 5)/(2 + 5) = 47.71
Example 3: The new statistical method results in a smaller statistical value, compared with the old statistical method.
Statistical dimension
Listener 1
Listener 2
Port number
8080
443
QPS
4
9
Response time (ms)
137
14
Old statistical method
(137 + 14)/2 = 75.5
New statistical method
(137 × 4)/(4 + 9) + (14 × 9)/(4 + 9) = 51.85
The following table lists the Layer 4 metrics for CLB. The protocol field in Dimensions is changed from HTTP or HTTPS to TCP due to the changes in the underlying data.
MetricName
MetricDescribe
Dimensions
Statistics
Unit
Alert granularity
ActiveConnection
Number of active connections to the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count
60s
DropConnection
Number of connections dropped on the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count/s
60s
DropPacketRX
Number of inbound packets dropped on the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count/s
60s
DropPacketTX
Number of outbound packets dropped on the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count/s
60s
DropTrafficRX
Number of inbound bits dropped on the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
bit/s
60s
DropTrafficTX
Number of outbound bits dropped on the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
bit/s
60s
InactiveConnection
Number of inactive connections on the listener
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count
60s
MaxConnection
Maximum number of connections supported by the listener per second
userId, instanceId, port, and protocol
Maximum, Minimum, and Average
count/s
60s
NewConnection
Number of new connections to the listener
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count
60s
PacketRX
Number of inbound packets to the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count/s
60s
PacketTX
Number of outbound packets from the listener per second
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
count/s
60s
TrafficRXNew
Inbound bandwidth of the listener
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
bit/s
60s
TrafficTXNew
Outbound bandwidth of the listener
userId, instanceId, port, and protocol
Average, Minimum, and Maximum
bit/s
60s