Cisco Cisco Email Security Appliance C190 Guia Do Utilizador

The system capacity page can be used to determine the following information:

Identify when a appliance is exceeding recommended capacity and configuration optimization or 
additional appliances are needed. 

Identify historical trends in system behavior which point to upcoming capacity issues. 

Identify which part of the system is using the most resources to assist with troubleshooting. 

It is important to monitor your appliance to ensure that your capacity is appropriate to your message 
volumes. Over time, volume will inevitably rise and appropriate monitoring will ensure that additional 
capacity or configuration changes can be applied proactively. The most effective way to monitor system 
capacity is to track overall volume, messages in the work queue and incidents of Resource Conservation 
Mode.

Volume: It is important to have an understanding of the “normal” message volume and the “usual” 
spikes in your environment. Track this data over time to measure volume growth. You can use the 
Incoming Mail and Outgoing Mail pages to track volume over time. For more information, see 

 and 

.

Work Queue: The work queue is designed to work as a “shock absorber”-- absorbing and filtering 
spam attacks and processing unusual increases in ham messages. However, the work queue is also 
the best indicator of a system under stress, prolonged and frequent work queue backups may indicate 
a capacity problem. You can use the WorkQueue page to track the average time messages spend in 
the work queue and the activity in your work queue. For more information, see 

.

Resource Conservation Mode: When a appliance becomes overloaded, it will enter “Resource 
Conservation Mode” (RCM) and send a CRITICAL system alert. This is designed to protect the 
device and allow it to process any backlog of messages. Your appliance should enter RCM 
infrequently and only during a very large or unusual increase in mail volume. Frequent RCM alerts 
may be an indication that the system is becoming overloaded. See 

The Workqueue page shows the average time a message spends in the work queue, excluding any time 
spent in the Spam quarantine or in a policy, virus, or outbreak quarantine. You can view time periods 
from an hour up to one month. This average can help in identifying both short term events delaying mail 
delivery and identify long term trends in the workload on the system.

If a message is released from the quarantine into the work queue, the “average time in work queue” 
metric ignores this time. This prevents double-counting and distorted statistics due to extended time 
spent in a quarantine.