Coyote Point Systems Equalizer Spezifikationen PDF herunterladen (Seite 364)

Configuring Server Connections

address. Since the cluster IP address is configured on the loopback interface of each server (See "Configuring

Direct Server Return" on page 313 ), one or more may respond to the ARP request. The client, and possibly even

the gateway, will then route requests for the cluster IP to servers directly without going through Equalizer. If this

occurs, you need to reconfigure the servers so that they do not respond to ARP requests for the cluster IP

addresses configured on the loopback interface. The procedure to follow to do this is specific to the operating

system running on the servers, so please consult the documentation for your server operating system.

Configuring a Cluster for Direct Server Return

The cluster dsr and spoof flags must be enabled for direct server return connections. In addition, the cluster idle

timeout parameter should be set as described in the table below:

l dsr - Enables Direct Server Return. All requests to this cluster IP will be forwarded to the server with the

client IP as the source IP, and the cluster IP as the destination IP. The loopback interface of the server

must be configured with the cluster IP to receive the requests.

l spoof - spoof causes Equalizer to spoof the client IP address when Equalizer routes a request to a server in

a virtual cluster; that is, the IP address of the client is sent to the server, not the IP address of the Equalizer.

This flag must be enabled for DSR.

l idle timeout - The time in seconds before reclaiming idle Layer 4 connection records. Applies to Layer 4

TCP clusters only. For DSR, idle timeout must be set to a non-zero value, or Equalizer will never reclaim

connection records for connections terminated by the server. The cluster's idle timeout should be set to

the longest period within your application that you would like Equalizer to wait for consecutive messages

from the client (since the Equalizer does not see server packets on DSR connections). For example, if the

longest expected server response time and the longest expected delay between client responses on active

connections are both 60 seconds, then set the idle timeout to 120 seconds.

The general procedure for configuring DSR on a new or existing cluster is as follows:

1. Enable the dsr and spoof flags on the cluster.

2. If the cluster is a Layer 4 TCP cluster and the idle timeout parameter is set to 0, increase it as described in

the table above.

3. Perform the procedure on each server in the server pool associated with the cluster.

Configuring Servers for Direct Server Return

1. Server configuration for DSR involves these basic steps:

2. Add a

loopback

network interface on the server.

3. Configure the loopback interface with the IP address and port of the DSR cluster.

4. Edit the configuration of the application on the server to listen for connections on the cluster IP and port. (An

HTTP server, for example, returns a Bad Hostname error to the client if there is an IP mismatch.)

5. Check the routing on your network to ensure that traffic is being routed as expected. For example, Equalizer

is usually

not

going to be used as the default gateway on your servers, since we want the servers to

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Coyote Point Systems Equalizer Spezifikationen Seite 364