Coyote Point Systems E350GX, Installation And Administration Manual

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Appendix B: Timeout Configuration
264 Equalizer Installation and Administration Guide
Note that if you change the
stale timeout
setting while partially established Layer 4 connections are currently in the
queue, those connections will be affected by the new setting.
Application Server Timeouts
Keep in mind that the application server running on the physical servers in your cluster may have its own timeout
parameters that will affect the length of time the server keeps connections to Equalizer and the client open. For
example, an Apache 2 server has two related timeout directives:
TimeOut and KeepAliveTimeout :
• The TimeOut directive currently defines the amount of time Apache will wait for three things:
• The total amount of time it takes to receive a GET request.
• The amount of time between receipt of TCP packets on a POST or PUT request.
• The amount of time between ACKs on transmissions of TCP packets in responses.
• The KeepAliveTimeout directive specifies the number of seconds Apache will wait for a subsequent
request before closing the connection. Once a request has been received, the timeout value specified by the
Timeout directive applies.
In general, if you want Equalizer to control connection timeouts, you must make sure that any timeouts set on the
application server are of longer duration than the values set on Equalizer.
For example, with respect to the Apache server timeouts above, the
client timeout
(for Layer 7 connections) or the
idle timeout
(for Layer 4 connections) should be of shorter duration than the timeouts set for Apache.
Similarly, the Layer 7
server timeout
and
connect timeout
on Equalizer should be of shorter duration than the TCP
connection timeouts set on the servers.
Connection Timeout Kernel Variables
Equalizer uses a number of kernel variables to track connection timeouts, as shown in the table below. You can use
the
sysctl
command to display kernel variables. The two basic formats of this command are:
sysctl variable_name
Displays the kernel variable variable_name.
sysctl -a > file
Displays all kernel statistics. This is a long list, so we recommend capturing the
list to a file.
eq.idle_timeout
The current setting of the Layer 4 global networking idle
timeout parameter.
eq.idle_timedout_count
A Layer 4 counter incremented when a connection is
terminated because the
idle timeout expired.
eq.stale_timeout
The current setting of the Layer 4 global networking stale
timeout parameter.
eq.l7lb.timeouts
The total number of Layer 7 connections dropped because a
connection timer expired.
eq.l7lb.http.client_timeouts
The total number of Layer 7 (HTTP and HTTPS) connections
that were terminated because the
client timeout expired.
eq.l7lb.http.connect_timeouts
The total number of Layer 7 (HTTP and HTTPS) connections
that were terminated because the
connect timeout
expired.
eq.l7lb.http.server_timeouts
The total number of Layer 7 (HTTP and HTTPS) connections
that were terminated because the
server timeout expired.