iTP Secure WebServer System Administrator's Guide (iTPWebSvr 6.0+)

Planning the iTP Secure WebServer PATHMON
Environment
iTP Secure WebServer System Administrator’s Guide—523346-002
3-3
Migration Considerations For Parallel Library TCP/IP
Support
Besides, it also posts a risk of losing a few connections when the PATHWAY removes
the dynamic servers. The Auto-Accept feature traded the Distributor with better
performance. The better performance is achieved by having the httpd servers accept
the new connection requests directly from transport layer (Parallel Library TCP/IP)
rather than having the Distributor accept the new connection and then distribute to
httpd servers.
Because the httpd servers are now picking the new connections by themselves,
removing an httpd server may disrupt the pending new connections (those connection
requests have been forwarded to the httpd server and has not yet picked up by the
httpd server). Unfortunately, the PATHWAY is unaware of these pending connections
and may remove a dynamic server when it has no more links with the Link Manager.
A further delay has been instrumented in the httpd server to complete all of its
outstanding pending connections before it does the exit. However, timing window may
still exist. Therefore, the new Deletedelay server directive is introduced to allow user to
specify a longer delay before a dynamic server is removed.
Deletedelay is documented in Server on page A-60.
A survey of the request load and a better planning are essentially to achieve a better
performance and non-disrupt Web server environment. Listed below are some of the
configuration guidelines recommended:
•
Specify at least the same number of static httpd servers as those CPUs intended
to run httpd servers. For example, if the httpd SERVERCLASS is configured to run
on CPU 0 to 5 (total of 6 CPUs), the Numstatic value should be at least 6. In fact,
tests have shown 3 httpd servers per CPU will achieve the best performance.
•
A higher value should be used for TANDEM_RECEIVE_DEPTH. The maximum
value support is 255. Depending on the speed of the CPU, higher value will
potentially reuse more sockets created for accepting new connections and save
more CPU cycles. Specifies a value lower than 50 may not be adequate.
•
Time your operation’s peak hours and off-peak hours, and specify an adequate
value for the Deletedelay. In other words, the dynamic servers will only be created
in the peak hours, specify a Deletedelay that will allow them to be removed only in
the off-peak hours. For example, if the peak operation hours are 11AM to 6PM,
specifying 7 hours of Deletedelay will allow the dynamic servers to be removed
after 6PM. But, if you have multiple peak hours, it may require more detailed
planning. The best way to avoid these types of problems is to make all of the httpd
servers static servers.