HP Integrity NonStop J-Series - Manual (Page 248)

4. Maxlinks – Determines the maximum number of TS/MP links. The number of simultaneous
messages that can be delivered to an instance of NSJSP is determined by Maxlinks. NSJSP
reads these many number of messages from the $RECEIVE file simultaneously.
5. Number of Connector threads.
The configurations for Numstatic, Maxservers, TANDEM_RECEIVE_DEPTH, and Maxlinks
can be set under the Server directive in the <iTP WebServer Deployment
Directory>/conf/servlet.config
file on OSS. Before trying to configure NSJSP, it is
important that you determine the maximum load that each instance of NSJSP is expected to
handle. The way these configuration directives drive the NSJSP environment depends on the
state of the SessionBasedLoadBalancing feature.
•
NSJSP configured with SessionBasedLoadBalancing turned OFF
•
NSJSP is configured with SessionBasedLoadBalancing turned ON
NSJSP configured with SessionBasedLoadBalancing turned OFF
•
The value of Numstatic must be [(Average Load)/(Max load one instance of
NSJSP can handle)]
.
•
Maxservers must be [(Peak Load)/(Max load one instance of NSJSP can
handle)] .
•
The value of Maxlinks must be set to the peak load that one instance of NSJSP is expected
to handle.
•
TANDEM_RECEIVE_DEPTH must be twice the value of Maxlinks. Normally, to handle n
number of messages, you need n number of threads. In extreme cases, all the n requests may
timeout. While the same number of threads processing the timeout requests can be busy, you
need the same n number of threads to process the new incoming requests. Therefore, the
number of threads that must be configured is (n + n = 2n).
•
The maximum number of connector thread, maxThreads must be equal to the value of
TANDEM_RECEIVE_DEPTH
.
For example:
The parameters Maxlinks, TANDEM_RECEIVE_DEPTH, and the Connector threads are closely
linked with each other. These parameters are explained using examples. The following examples
assume that the httpd processes are configured to serve 100 simultaneous HTTP, and all 100
HTTP requests are serviced by your MyFaces application deployed in NSJSP (that is, there is no
static content in the application). Also, the peak load that one single instance of NSJSP can handle
is 25.
Because SessionBasedLoadBalancing is turned OFF, all messages between HTTPD and
NSJSP
flow through TS/MP. The number of simultaneous messages that can be delivered to an
instance of NSJSP is determined by the value of Maxlinks; set the value of Maxlinks to 25.
NSJSP can now read 25 messages from its $RECEIVE queue simultaneously. In an extreme case,
all the 25 messages time out; there must be enough space in the $RECEIVE queue to accommodate
25 more messages. Therefore, $RECEIVE must be opened with a Receive Depth (controlled
by TANDEM_RECEIVE_DEPTH) of (25+25). Thus, you must set the value of
TANDEM_RECEIVE_DEPTH
to 50. The reason for setting TANDEM_RECEIVE_DEPTH to a value
of 50 can be explained as:
To handle 25 messages, you need 25 threads. In an extreme case where all the 25 requests time
out, you need another 25 threads to process the new incoming 25 requests because the threads
processing the timeout requests could still be busy. Therefore, the number of threads that need to
be configured is (25+25 = 50).
248 Configuring MyFaces Applications on NonStop Systems