Novonyx Enterprise Server Performance Tuning.

(Last modified: 10Aug2001)

This document (10015872) is provided subject to the disclaimer at the end of this document.

goal

fact

Formerly TID 2935075

fix

You can configure the server's technical options including:

1. the number of maximum simultaneous requests. 2. Enabling Domain Name System lookups
3. listen-queue size
4. Configuring the HTTP persistent connection timeout

Configuring maximum simultaneous requests

You can set the number of maximum simultaneous requests, which is the number of active requests allowed for the server at one time. However, for general purpose Internet or Intranet use, you probably will not need to change the default value (128 requests).

To get the number of simultaneous requests, the server counts the number of active requests, adding 1 to the number when a new request arrives, subtracting 1 when it finishes the request. 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.

In theory, you could set the maximum simultaneous requests to 1 and still have a functional server. Setting this value to 1 would mean that the server could only handle one request at a time, but since HTTP requests generally have a very short duration (response time can be as low as 5 milliseconds), processing one request at a time would still allow you to process up to 200 requests per second.

However, in actuality, Internet client frequently connect to the server and then do not complete their requests. In these cases, the server waits 30 seconds or more for the data before timing out. Also, some sites do heavyweight transactions that take minutes to complete. Both of these factors add to the maximum simultaneous requests that are required. If your site is processing many requests that take many seconds, you may need to increase the number of maximum simultaneous requests.

If you need to change the number of maximum simultaneous requests, set the number before starting the server. To reset the number:

  1.Choose Server Preferences|Performance Tuning.
  2.Type the number of requests.
  3.Click OK.
  4.Click Save and Apply.

Enabling Domain Name System lookups

You can configure the server to use Domain Name System (DNS) lookups during normal operation. By default, DNS is not enabled; if you enable DNS, the server looks up the host name for a system's IP address. Although DNS lookups can be useful for server administrators when looking at logs, they can impact performance. When the server receives a request from a client, the client's IP address is included in the request. If DNS is enabled, the server must look up the hostname for the IP address for every client making a request.

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.

Note

Turning off DNS lookups on your server has the following consequences: host name restrictions won't work, and hostnames won't appear in your log files. Instead, you'll see IP addresses.

You can also specify whether to cache the 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. You can specify the size of the DNS cache and an expiration time for DNS cache entries. The DNS cache can contain 32 to 32768 entries; the default value is 1024 entries. Values for the time it takes for a cache entry to expire can range from 1 second to 1 year (specified in seconds); the default value is 1200 seconds (20 minutes).

Configuring listen-queue size

The listen-queue size is a socket-level parameter that specifies the number of incoming connections the system will accept for that socket. The default setting is 100 incoming connections.

Note

Normally, you should not change the listen-queue size. The default setting is sufficient in most cases.

If you manage a heavily used web site, you should make sure your system's listen-queue size is large enough to accommodate the listen-queue size setting from the Server Manager form. If you do change the listen-queue size, make sure that your system supports the new size. The listen-queue size set from the Server Manager form changes the listen-queue size requested by the server. If the server requests a listen-queue size larger than the system's maximum listen-queue size, the size defaults to the system's maximum.

Caution!

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.

Configuring the HTTP persistent connection timeout

With HTTP 1.1, a connection can be set to be persistent (similar to keep alive in HTTP 1.0). However, even if a connection is persistent, it still needs to have a timeout setting, or it may consume system resources.

NOTE:

Normally, you should not change the persistent connection timeout. The default setting is sufficient in most cases.

If you need to change the setting:

  1.From the Server Manager, choose Server Preferences | Performance Tuning.
  2.Enter a number in seconds in the HTTP Persistent Connection Timeout field.
  3.Click OK.
  4.Save and apply your changes.

document

Document Title:	Novonyx Enterprise Server Performance Tuning.
Document ID:	10015872
Solution ID:	1.0.1439723.2308771
Creation Date:	06Sep1999
Modified Date:	10Aug2001
Novell Product Class:	Connectivity Products Groupware Novonyx

disclaimer

The Origin of this information may be internal or external to Novell. Novell makes all reasonable efforts to verify this information. However, the information provided in this document is for your information only. Novell makes no explicit or implied claims to the validity of this information.
Any trademarks referenced in this document are the property of their respective owners. Consult your product manuals for complete trademark information.