Use this page to configure the HTTP server performance settings.
The following table describes the fields and buttons on the page. The left column lists the fields and buttons; the right column describes the functionality.
Field or Button
|
Description
|
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Maximum Simultaneous Connections |
Specifies an upper limit on the number of simultaneous requests accepted by the server. When a new request arrives, the server checks to see if it is already processing the maximum number of requests. If it has reached the limit, it defers processing new requests until the number of active requests drops below the maximum amount. Default is 128. |
DNS Enabled |
Allows you to enable the server to do a reverse lookup of a client's IP in the DNS database before executing a CGI script. Servlets also depend on this flag to do reverse lookup. DNS lookups can slow performance, especially on a server that uses extensive CGIs. By default, DNS lookups are not allowed. Instead, hosts are identified by IP address in the CGI environment and in log files. |
Async DNS Enabled |
Specifies whether asynchronous DNS is enabled. DNS causes multiple threads to be serialized when you use DNS services. If you do not want serialization, enable asynchronous DNS. You can enable it only if you have also enabled DNS. Enabling asynchronous DNS can improve your system's performance if you are using DNS. |
DNS Cache Enabled |
Determines whether to cache DNS entries. If you enable the DNS cache, the server can store hostname information after receiving it. If the server needs information about the client in the future, the information is cached and available without further querying. Caching DNS entries may slow down the server. |
Size of DNS Cache |
Specifies the number of entries in the DNS cache if you have enabled DNS. The DNS cache can contain 32 to 32768 entries; the default value is 512 entries. |
Expire Entries (sec) |
Specifies the number of seconds to allow before DNS entries are deleted from the cache if you have enabled DNS. Cache entry expiration time can range from 1 second to 1 year (specified in seconds); the default value is 1200 seconds (20 minutes). |
Listen Queue Size |
Determines the number of incoming connections the system will accept for that socket. If you manage a heavily used site, make sure your system's listen-queue size is large enough to accommodate the listen-queue size setting from Sun ONE Application Server. Setting the listen-queue size too high can degrade server performance. The listen-queue size was designed to prevent the server from becoming overloaded with connections it cannot handle. If your server is overloaded and you increase the listen-queue size, the server will only fall further behind. |
HTTP Persistent Connection Timeout |
Specifies the number of seconds the server allows a client connection to remain open with no activity. A client may keep a connection to the server open so that multiple requests to one server can be serviced by one network connection. Since a given server can handle a finite number of open connections (limited by active threads), a high number of open connections will prevent new clients from connecting. Setting the timeout to a lower value, however, may prevent the transfer of large files as timeout does not refer to the time that the connection has been idle. |
OK |
Saves your entries. |
Reset |
Resets the values on the page to the default values. |
See also | |
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Sun ONE Application Server Performance Tuning and Sizing Guide |