Cisco Cisco Email Security Appliance X1070 Troubleshooting Guide
ESA FAQ: What is Resource Conservation mode
on the ESA?
on the ESA?
Document ID: 117834
Contributed by Nasir Shakour and Enrico Werner, Cisco TAC
Engineers.
Jun 24, 2014
Engineers.
Jun 24, 2014
Contents
Introduction
What is Resource Conservation mode on the ESA?
GUI
CLI
What is Resource Conservation mode on the ESA?
GUI
CLI
Introduction
This document describes what Resource Conservation mode on the Cisco Email Security Appliance (ESA) is.
What is Resource Conservation mode on the ESA?
Resource Conservation mode is a self−protective mode that the ESA enters when it is short on internal
system resources. For example, when RAM utilization goes above 75% of capacity, AsyncOS will enter into
Resource Conservation mode. A shortage of any of several resources, including queue space, can cause the
system to enter into Resource Conservation mode.
system resources. For example, when RAM utilization goes above 75% of capacity, AsyncOS will enter into
Resource Conservation mode. A shortage of any of several resources, including queue space, can cause the
system to enter into Resource Conservation mode.
Fundamentally, Resource Conservation mode is entered when the rate of messages coming into an ESA is
higher than the rate of messages leaving the appliance. Although differentials in these rates are common, if the
incoming rate exceeds the delivery rate for a long period of time or by a huge differential, the appliance does
not have the resources to store additional messages.
higher than the rate of messages leaving the appliance. Although differentials in these rates are common, if the
incoming rate exceeds the delivery rate for a long period of time or by a huge differential, the appliance does
not have the resources to store additional messages.
The goal behind Resource Conservation mode is to slow down traffic coming into the ESA so that the
delivery rate can exceed the acceptance rate and drain messages out of the system.
delivery rate can exceed the acceptance rate and drain messages out of the system.
Resource Conservation mode is not an on/off switch. When AsyncOS enters Resource Conservation mode, it
gradually slows down the rate at which it will accept messages to try and balance the incoming and outgoing
message rates. In extreme cases where resources are totally exhausted, AsyncOS will refuse to accept new
messages.
gradually slows down the rate at which it will accept messages to try and balance the incoming and outgoing
message rates. In extreme cases where resources are totally exhausted, AsyncOS will refuse to accept new
messages.
When AsyncOS enters Resource Conservation mode, it sends an alert message. If you have configured alerts
using alertconfig, you will receive a copy of this alert.
using alertconfig, you will receive a copy of this alert.
Note: The alert does not go through the normal AsyncOS mail system, and thus can be delivered even when
other message delivery is halted. When AsyncOS leaves Resource Conservation mode, you will receive
another alert.
other message delivery is halted. When AsyncOS leaves Resource Conservation mode, you will receive
another alert.
You can see Resource Conservation mode in both the GUI and in the CLI.