iTP Secure WebServer System Administrators Guide (Version 7.5+)

conventional TCP/IP, a TCP/IP process is usually running on two processors a primary and
a backup.
For TCP/IPv6 or IP CIP, if the application is running on all the other 14 processors, and then
all of those need to be TCP/IPv6 or IP CIP-enabled and must be in the access list.
TCP/IPv6 or IP CIP-enabled means that a TCP6MON process must be running on that processor.
For the httpd servers to function properly, all these processes must be in place. Socket errors
will be reported if a TCP6MON is not running on a processor that attempts to run an httpd
process. If the bind request fails, the httpd server is designed to retry the request. Repeated
bind failures might indicate that a processor is not TCP/IPv6 or IP CIP-enabled.
NOTE: The following conditions are applicable for TCP/IPv6 and IP CIP.
• Use One TCP6SAM Process
Check that there is one TCP6SAM process pair running on any two processors in the system.
HP recommends that you use only one TCP6SAM process pair - even where you are using
more than one IP address. Unlike the conventional TCP/IP processes, one TCP6SAM process
can provide socket interfaces for all IP addresses configured in the TCP/IPv6 or IP CIP
environment. If you use more than one, two httpd servers might attempt access to the same
port and therefore generate EADDRINUSE socket errors.
• Use Static Servers
HP recommends that you run as many static servers as you might need. Creating dynamic
servers is known to be expensive and will severely affect response time - especially for the
request waiting for the dynamic server to be created. In addition, dynamic servers can drop
one or two connections when the Deletedelay effect occurs. Because all the httpd servers are
designed to run on high PIN, creating more servers at the startup should not create a resource
problem.
• Specify a Larger Tandem_Receive_Depth
The range is 1 to 255. The default is 50. Selecting a larger number prevents extra pathsends
and possible socket migration. When the connection request is sent to a server that is not
running on the same processor as the original listening agent, a socket migration occurs and
a performance penalty is incurred. A larger number also prevents the creation of dynamic
servers. Creating an additional httpd server on a processor that already has a number of httpd
servers running is neither going to help distribute the load nor improve performance. The load
distribution has now been moved down to the adapter level by use of the round-robin filter.
Additional processes can create more dispatching costs for the processor.
• Specify the -address Command in All Accept Directives
You should use the -address command in all Accept directives. Unlike the conventional TCP/IP
processes TCP6SAM allows the httpd servers to interface with all subnets configured in the
TCP/IPv6 or IP CIP environment. The "accept ALL IP addresses" is literally ALL IP addresses
defined in the entire system. This might be more than you expected.
• Rebalancing Servers Across processors
When a processor is brought down, PATHMON is likely to restart a number of static servers
on other processors to keep the number of static servers as specified in the NUMSTATIC server
attribute. When the processor is reloaded, PATHMON will not automatically rebalance its
servers among the processors. If there are extensive reloads you might want to rebalance
manually - using actions ranging from a simple stopping of one or two servers, to a complete
36 Installing the iTP Secure WebServer