Installation guide

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Device Manager Guide, Cisco ACE 4700 Series Application Control Engine Appliance
OL-26645-02
Chapter 6 Configuring Real Servers and Server Farms
Configuring Health Monitoring
VM Probe Attributes
Note Use a VM probe when you configure the ACE for Dynamic Workload Scaling (see the “Configuring
Dynamic Workload Scaling” section on page 6-14).
Configure the VM probe attributes to control when the ACE bursts traffic to remote VMs based on an
average of local VM CPU usage, memory usage, or both. The ACE obtains the usage information by
sending the VM probe to the specified VM Controller associated with the local VMs It calculates the
average aggregate load information for all local VMs as a percentage of CPU usage or memory usage
and uses either or both percentages to determine when to burst traffic to the remote data center. If the
server farm consists of both physical servers and VMs, the ACE considers load information only from
the VMs.
By default, the VM probe checks the percentage of usage for either the CPU or memory against the
maximum threshold value. Whichever percentage reaches its maximum threshold value first causes the
ACE to burst traffic to the remote data center. The default maximum burst threshold value of 99 percent
instructs the ACE to always load balance traffic to the local VMs unless the load value is equal to
100 percent or the VMs are not in the OPERATIONAL state. If you configure the maximum burst
threshold value to1 percent, the ACE always bursts traffic to the remote data center.
When the usage percentage is less than the minimum threshold value, the ACE stops bursting traffic to
the remote data center and continues to load balance traffic to the local VMs. Any active connections to
the remote data center are allowed to complete.
Table 6-31 lists the VM probe attributes, which allow you to control when the ACE bursts traffic to
remote VMs.
Related Topics
• Configuring Dynamic Workload Scaling, page 6-14
Table 6-31 VM Probe Attributes
Field Action
Probe Interval (seconds) Frequency in seconds with which the ACE sends probes to the VM controller. Enter an integer
from 300 to 65535. The default is 300 (5 minutes).
Max CPU Burst
Threshold
Threshold for the maximum percentage of the CPU usage based on the average load information
for all local VMs. When the CPU usage percentage reaches or exceeds this threshold, the ACE
starts bursting traffic to the remote VMs. Enter a value from 1 to 99. The default is 99.
Min CPU Burst
Threshold
Threshold for the minimum percentage of the CPU usage based on the average load information
for all local VMs. When the CPU usage percentage drops below this threshold, the ACE stops
bursting traffic to the remote VMs. Enter a value from 1 to 99 percent. The default is 99.
Max Memory Burst
Threshold
Threshold for the maximum percentage of the memory usage based on the average load
information for all local VMs. When the memory usage percentage reaches or exceeds this
threshold, the ACE starts bursting traffic to the remote VMs. Enter a value from 1 to 99 percent.
The default is 99
Min Memory Burst
Threshold
Threshold for the minimum percentage of the memory usage based on the average load
information for all local VMs. When the memory usage percentage drops below this threshold, the
ACE stops bursting traffic to the remote VMs. Enter a value from 1 to 99 percent. The default is 99.
VM Controller Name Identifier of the VM controller that you configured in the “Configuring and Verifying a VM
Controller Connection” section on page 6-16. Click the radio button for the VM controller.