Coyote Point Systems Equalizer Spezifikationen PDF herunterladen (Seite 303)

About Passive FTP Translation

In version 8.6 if your servers were on a network that the outside world could not reach, you were provided the

capability of enabling a passive FTP translation option. This option caused Equalizer to rewrite outgoing FTP

PASV control messages from the servers so they could contain the IP address of the virtual cluster rather than

that of the server. This was a global option.

In building EQ OS 10 our experience indicated that the great majority of customers using FTP wanted this option

turned ON. With that "passive FTP translation" is now always ON. It is set internally and there is no user interface

control to turn it OFF. Our analysis leads us to believe that the only reason to turn it OFF would be in a high-

bandwidth FTP server farm that supports "active FTP" only.

Contact customer support for instructions if you require this feature to be turned OFF.

Enabling Cookies for Persistent Connections

For Layer 7 HTTP and HTTPS clusters, you can enable the persist check box to use cookies to maintain a

persistent session between a client and a particular server for the duration of the session.

When you use cookie-based persistence, Equalizer inserts a cookie into the server’s response header on its way

back to the client. This cookie uniquely identifies the server to which the client was connected and is included

automatically in subsequent requests from the client to the same cluster. Equalizer can use the information in the

cookie to route the requests to the same server. If the server is unavailable, Equalizer automatically selects a

different server.

This option is enabled by default. Also see the descriptions of the always, cookie age, cookie domain, and cookie

path cluster parameters under "Modifying a Layer 7 HTTP or HTTPS Cluster" on page 282.

Enabling Persistent Server Connections

Equalizer provides several methods by which connections between clients and servers can be made

persistent

;

that is, it is possible to route a series of requests from a particular client to the same server, rather than have the

Equalizer load balance each request in the series -- potentially sending each request to a different server.

l For Layer 4 clusters, persistent server connections are enabled using the Sticky Time cluster parameter

and (optionally) the Inter-Cluster Sticky cluster flag.

l For Layer 7 clusters, persistent server connections are enabled using the Persist and Always cluster flags.

Enabling Sticky Connections

For Layer 4 TCP and UDP clusters, you can use IP-address based sticky connections to maintain persistent

sessions.

The sticky time period is the length of time over which Equalizer ensures that it directs new connections from a

particular client to the same server. The timer for the sticky time period begins to expire as soon as there are no

active connections between the client and the cluster. If Equalizer establishes a new connection to the cluster,

Equalizer resets the timer for the sticky time period.

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Equalizer Administration Guide

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Coyote Point Systems Equalizer Spezifikationen Seite 303