Chapter 6   Tuning the Operating System


There are a couple of Solaris® network performance tuning tricks that do not directly benefit iPlanet Application Server, but may be useful for other socket intensive customer applications that run in a data center application suite.

Tuning Solaris TCP/IP settings benefit programs that open and close a lot of sockets. iPlanet Application Server operates with a small fixed set of connections and the performance gain may not be as significant on the Application Server node. iPlanet Web Server and iPlanet Web Servers configured as a Web front-end to iPlanet Application Server can benefit significantly.

To retain these changes, after rebooting, set ndd variables in the file: /etc/rc2.d/S69inet.

This chapter discusses the following topics:

• Setting Time Wait Interval

• Setting TCP Connection Hash Table Size

• Binding Processes

Setting Time Wait Interval

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After a connection has been closed by both the client and the server, the port remains unavailable for a certain amount of time, so that a new program does not inadvertently get packets that were intended for the old program. On Solaris machines, the default value of tcp_time_wait_interval is 240,000 ms (4 minutes). It is recommended that this be set at 60000 ms (1 minute) or even at 30000 (30 seconds) for better performance in socket communication intensive programs. The value can be modified and examined on a running system.

/usr/sbin/ndd -set /dev/tcp tcp_time_wait_interval 60000

/usr/sbin/ndd -get /dev/tcp tcp_time_wait_interval

Setting TCP Connection Hash Table Size

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The connection hash table keeps all the information for active TCP connections (ndd -get /dev/tcp tcp_conn_hash). This value does not limit the number of connections, but it can cause connection hashing to take longer. To make lookups more efficient, set the value to half of the number of concurrent TCP connections that you expect on the server (netstat -nP tcp|wc -l, gives you a number). It defaults to 512. This can only be set in /etc/system and becomes effective at boot time.

set tcp:tcp_conn_hash_size=8192

Binding Processes

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Binding the Application Server processes to one or more processors used to produce significant performance gains (20%-30%) on earlier versions of iPlanet Application Server running on Solaris. However with SP2 and later release on Solaris 8, no significant gains were observed. We therefore do not recommend this setting.