Coyote Point Systems Equalizer, Installation And Administration Manual

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Cluster-Specific Parameters
Equalizer Installation and Administration Guide 115
request_max
This is the maximum amount of bytes, specified in KBytes, of a valid request, for all
requests supported by the cluster. If a request is received which exceeds this, the request
will be dropped (the connection to the client will be closed).
Minimum: 4 (4KB), Maximum: 64 (64KB), Default: 32 (32KB)
Judicious use of this, in conjunction with the receive_socket_buffer, can be used to ensure
that misbehaved clients cannot waste resources on the Equalizer.
For the Equalizer to simultaneously handle X L7 requests for a cluster, it must have in
excess of “request_max” times X KBytes of non-swappable kernel memory allocated to the
network as mbufs; otherwise, it is possible to deadlock and not be able to make further
progress.
Flags
The flags that can be set within a cluster body depends on the protocol.
For L4 UDP and L4 TCP, the following flags are defined.
■
none—Clear any flags set. This facilitates turning off any flag settings inherited from
he global environment.
■
spoof —Enable client address spoofing. For L7 clusters, the Equalizer terminates the
TCP connection. This means that the server eventually selected will think that the
client address is that of the Equalizer, unless spoofing is enabled. Just the IP address is
spoofed, not the port.
■
inter_cluster_sticky—When enabled, Equalizer ensures that requests from a particular
user are directed to the same server, even if the connection is to a different virtual
cluster. (Only set for generic TCP and UDP clusters that support L4 load balancing.)
■
disable—A cluster can be disabled from functioning by setting this flag.
For L7 HTTP, the following flags are defined.
■
ssl_unclean_shutdown—This is reserved for future functionality.
HTTP-Specific Cluster Parameters
When the HTTP protocol is selected for a cluster, the following additional parameters are
defined.
cookie_scheme
Different schemes can be used for encoding the persistence information in the cookie.
Currently, the only one supported is scheme 1.
cookie_max_age
This provides the numeric value, in seconds, for the “Max-Age” cookie parameter, which
if specified, will cause the client browser to eliminate the cookie after the specified number
of seconds have elapsed.