Sun Java System Web Server is designed to meet the needs of the most demanding, high-traffic sites in the world. It runs flexibly on UNIX, Linux, and Windows, and can serve both static and dynamically generated content. Sun Java System Web Server can also run in SSL mode, enabling the secure transfer of information.
This guide helps you to define your server workload and size a system to meet your performance needs. Your environment is unique, however, so the impacts of the suggestions provided here also depend on your specific environment. You must rely on your own judgement and observations to select the adjustments that are best for you.
This chapter provides a general discussion of server performance considerations, and more specific information about monitoring server performance.
This chapter includes the following topics:
The first step toward sizing your server is to determine your requirements. Performance means different things to users than to webmasters. Users want fast response times (typically less than 100 milliseconds), high availability (no “connection refused” messages), and as much interface control as possible. Webmasters and system administrators, on the other hand, want to see high connection rates, high data throughput, and uptime approaching 100%. In addition, for virtual servers the goal might be to provide a targeted level of performance at different price points. You need to define what performance means for your particular situation.
Here are some areas to consider:
The number of peak concurrent users
Encrypting your Sun Java System Web Server’s data streams with SSL makes an enormous difference to your site’s credibility for electronic commerce and other security conscious applications, but it can also seriously impact your CPU load. SSL always has a significant impact on throughput, so for best performance minimize your use of SSL, or consider using a multi-CPU server to handle it.
The size of the document tree
Dynamic versus static content
The content you serve affects your server’s performance. A Sun Java System Web Server delivering mostly static HTML can run much faster than a server that must execute CGIs for every query.
Virtual servers add another layer to the performance improvement process. Certain settings are tunable for the entire server, while others are based on an individual virtual server. You can also use the quality of service (QOS) features to set resource utilization constraints for an individual virtual server or class of virtual servers. For example, you can use QOS features to limit the number of connections allowed for a virtual server or class of virtual servers.
For more information about using the quality of service features, see the Sun Java System Web Server 6.1 SP6 Administrator’s Guide.
Making the adjustments described in this guide without measuring their effects does not make sense. If you don’t measure the system’s behavior before and after making a change, you won’t know whether the change was a good idea, a bad idea, or merely irrelevant. You can monitor the performance of Sun Java System Web Server in several different ways, as discussed in the following topics:
You must activate statistics on Sun Java System Web Server before you can monitor performance. This can be done through the Server Manager, or by editing the obj.conf and magnus.conf files.
When you activate statistics/profiling, statistics information is made available to any user of your server.
You can activate statistics from the user interface.
From the Server Manager, click the Monitor tab, and then click Monitor Current Activity.
The Enable Statistics/profiling page appears.
Select Yes to activate Statistics/Profiling.
Click OK, click Apply, and then click the Apply Changes button to activate Statistics/Profiling.
You can also activate statistics directly by editing the obj.conf and magnus.conf files. Users who create automated tools or write customized programs for monitoring and tuning may prefer to work directly with stats-xml.
Under the default object in obj.conf, add the following line:
NameTrans fn="assign-name" from="/stats-xml/*" name="stats-xml"
Add the following Service function to obj.conf:
<Object name="stats-xml"> Service fn="stats-xml" </Object>
Add the stats-init SAF to magnus.conf.
Here's an example of stats-init in magnus.conf:
Init fn="stats-init" update-interval="5" virtual-servers="2000" profiling="yes"
The above example shows you can also designate the following:
virtual-servers. The maximum number of virtual servers for which you track statistics. This number should be set equal to or higher than the number of virtual servers configured. Smaller numbers result in lower memory usage. The minimum value is 1; the default is 1000.
profiling. Activate NSAPI performance profiling. The default is "no," which results in slightly better server performance. However, if you activate statistics through the user interface, profiling is turned on by default.
Once you’ve activated statistics, you can get a variety of information on how your server instance and your virtual servers are running. The statistics are broken up into functional areas.
From the Server Manager, click the Monitor tab, and then click Monitor Current Activity.
To ensure that statistics/profiling is activated ("Yes" is selected and applied for "Activate Statistics/Profiling?").
From the drop-down list, select a refresh interval.
From the drop-down list, select the type of web server statistics to display.
A page appears displaying the type of statistics you selected. The page is updated every 5-15 seconds, depending on the refresh interval. All pages will display a bar graph of activity, except for Connections.
Select the process ID from the drop-down list.
You can view the current activity through the Server Manager, but these categories are not fully relevant for tuning your server. The perfdump statistics is recommended for tuning your server. For more information, see Using Statistics to Tune Your Server
Virtual server statistics can be viewed from the Server Manager. You can choose to display statistics for the server instance, for an individual virtual server, or for all. This information is not provided through perfdump.
The perfdump utility is a Server Application Function (SAF) built into Sun Java System Web Server that collects various pieces of performance data from the Web Server internal statistics and displays them in ASCII text. The perfdump utility allows you to monitor a greater variety of statistics than those available through the Server Manager.
With perfdump, the statistics are unified. Rather than monitoring a single process, statistics are multiplied by the number of processes, which gives you a more accurate view of the server as a whole.
<Object name="perf">Service fn="service-dump"</Object>
Add the following to the default object:
NameTrans fn=assign-name from="/.perf" name="perf"
Make sure that the .perf NameTrans directive is specified before the document-root NameTrans directive in the default object.
If not already activated, activate stats-xml.
For more information, see Activating Statistics
Restart your server software.
Access perfdump by entering this URL:
You can request the perfdump statistics and specify how frequently (in seconds) the browser should automatically refresh. The following example sets the refresh to every 5 second
The following is sample perfdump output:
------------------------------------------------------------ webservd pid: 2408 ConnectionQueue: ---------------------------------- Current/Peak/Limit Queue Length 0/0/4096 Total Connections Queued 0 Average Queueing Delay 0.00 milliseconds ListenSocket ls1: ------------------------ Address http://0.0.0.0:8080 Acceptor Threads 1 Default Virtual Server https-iws-files2.red.iplanet.com KeepAliveInfo: -------------------- KeepAliveCount 0/256 KeepAliveHits 0 KeepAliveFlushes 0 KeepAliveRefusals 0 KeepAliveTimeouts 0 KeepAliveTimeout 30 seconds SessionCreationInfo: ------------------------ Active Sessions 1 Total Sessions Created 48/128 CacheInfo: ------------------ enabled yes CacheEntries 0/1024 Hit Ratio 0/0 ( 0.00%) Maximum Age 30 Native pools: ---------------------------- NativePool: Idle/Peak/Limit 1/1/128 Work Queue Length/Peak/Limit 0/0/0 Server DNS cache disabled Async DNS disabled Performance Counters: ------------------------------------------------ Average Total Percent Total number of requests: 0 Request processing time: 0.0000 0.0000 default-bucket (Default bucket) Number of Requests: 0 ( 0.00%) Number of Invocations: 0 ( 0.00%) Latency: 0.0000 0.0000 ( 0.00%) Function Processing Time: 0.0000 0.0000 ( 0.00%) Total Response Time: 0.0000 0.0000 ( 0.00%) Sessions: ---------------------------- Process Status Function 2408 response service-dump ------------------------------------------------------------
Performance buckets allow you to define buckets and link them to various server functions. Every time one of these functions is invoked, the server collects statistical data and adds it to the bucket. For example, send-cgi and NSServletService are functions used to serve the CGI and Java servlet requests respectively. You can either define two buckets to maintain separate counters for CGI and servlet requests, or create one bucket that counts requests for both types of dynamic content. The cost of collecting this information is little and impact on the server performance is usually negligible. This information can later be accessed using the perfdump utility. The following information is stored in a bucket:
Name of the bucket. This name is used for associating the bucket with a function.
Description. A description of the functions that the bucket is associated with.
Number of requests for this function. The total number of requests that caused this function to be called.
Number of times the function was invoked. This number may not coincide with the number of requests for the function because some functions may be executed more than once for a single request.
Function latency or the dispatch time. The time taken by the server to invoke the function.
Function time. The time spent in the function itself.
First, you must enable performance measurement as described in Monitoring Current Activity Using the perfdump Utility
Init fn="define-perf-bucket" name="acl-bucket" description="ACL bucket" Init fn="define-perf-bucket" name="file-bucket" description="Non-cached responses" Init fn="define-perf-bucket" name="cgi-bucket" description="CGI Stats"
The example above creates three buckets: acl-bucket, file-bucket, and cgi-bucket. To associate these buckets with functions, add bucket=bucket-name to the obj.conf function for which you wish to measure performance.
PathCheck fn="check-acl" acl="default" bucket="acl-bucket" ... Service method="(GET|HEAD|POST)" type="*~magnus-internal/*" fn="send-file" bucket="file-bucket" ... <Object name="cgi"> ObjectType fn="force-type" type="magnus-internal/cgi" Service fn="send-cgi" bucket="cgi-bucket" </Object>
The server statistics in buckets can be accessed using the perfdump utility. The performance buckets information is located in the last section of the report returned by perfdump.
The report contains the following information:
Average, Total, and Percent columns give data for each requested statistic.
Request Processing Time is the total time required by the server to process all requests it has received so far.
Number of Requests is the total number of requests for the function.
Number of Invocations is the total number of times that the function was invoked. This differs from the number of requests in that a function could be called multiple times while processing one request. The percentage column for this row is calculated in reference to the total number of invocations for all of the buckets.
Latency is the time in seconds Sun Java System Web Server takes to prepare for calling the function.
Function Processing Time is the time in seconds Sun Java System Web Server spent inside the function. The percentage of Function Processing Time and Total Response Time is calculated with reference to the total Request Processing Time.
Total Response Time is the sum in seconds of Function Processing Time and Latency.
Performance Counters: ------------------------------------------------ Average Total Percent Total number of requests: 0 Request processing time: 0.0000 0.0000 default-bucket (Default bucket) Number of Requests: 0 ( 0.00%) Number of Invocations: 0 ( 0.00%) Latency: 0.0000 0.0000 ( 0.00%) Function Processing Time: 0.0000 0.0000 ( 0.00%) Total Response Time: 0.0000 0.0000 ( 0.00%)