User Guide

308 Chapter 13 Maintaining Cluster Members
Understanding ClusterCATS Server Modes
ClusterCATS allows you to move cluster members into various modes of operation
depending on the tasks you want to perform on that server. These modes allow you
to remove servers from clusters to perform maintenance activities without
disturbing the current traffic flow among other things.
The following table describes the various modes of operation that ClusterCATS
allows you to put cluster members into:
Mode Description
Active/Passive Setting Turns on and off the ClusterCATS Server. In Active state,
the ClusterCATS Server intercepts HTTP requests and
processes them for load balancing and availability. In
Passive state, all HTTP requests are passed directly to the
Web server without the ClusterCATS Server intercepting
them.
For more information on Activating/Deactivating
ClusterCATS Servers, refer to “Changing Active/Passive
Settings” on page 309.
Restricted/Unrestricted
Setting
Determines whether Active cluster members receive any
HTTP traffic. Restricted ClusterCATS Servers do not
receive any HTTP traffic. Unrestricted ClusterCATS
Servers are sent traffic as normal.
For more information on setting ClusterCATS Servers to
Restricted or Unrestricted mode, refer to “Changing
Restricted/Unrestricted Settings” on page 311.
Maintenance Mode Allows you to gracefully remove a server from a cluster by
draining off all users without cutting connections. This is
typically used when you want to upgrade a server or
remove it entirely from the cluster.
For more information on putting clusters in and out of
Maintenance mode, refer to “Using Maintenance Mode
(Windows only)” on page 313.
Note that only Windows cluster members can be put in
Maintenance mode.