The PerfServlet is used for simple end-to-end retrieval
of performance data that any tool, provided by either IBM or a third-party
vendor, can handle.
Before you begin
The servlet provides a way to use an HTTP request to query
the performance metrics for an entire WebSphere Application Server
administrative domain. Because the servlet provides the performance
data through HTTP, issues such as firewalls are trivial to resolve.
The
PerfServlet provides the performance data output as an XML document,
as described in the provided document type description (DTD). In the
XML structure, the leaves of the structure provide the actual observations
of performance data and the paths to the leaves that provide the context.
Best practice: The PerfServlet is a
sample monitoring tool that uses WebSphere Application Server administration
and monitoring interfaces to expose performance data. Using the PerfServlet
is not intended for real-time performance monitoring in production
environments or for use in large topologies. For these environments
you should use the Tivoli Performance Viewer or ITCAM (IBM Tivoli
Composite Application Manager) for WebSphere Application Server.
Specific
best practices for the PerfServlet are the following:
- PerfServlet overhead: The PerfServlet is not designed to
run concurrently. Being a single threaded servlet, it would collect
the data sequentially from available servers. This single threaded
operation can cause higher response times when the PerfServlet is
used in larger deployments.
- PerfServlet in large deployments:
- By default, when the PerfServlet is first initialized, it retrieves
the list of nodes and servers within the cell in which it is deployed.
Because collecting this data costs in system processing time, the
PerfServlet holds this information as a cached list. To force the
servlet to refresh its configuration, you can use the option "refreshconfig=true".
However, using this option is not recommended unless required, because
this option adds extra overhead to the PerfServlet processing.
- Use option, node and server, if you are looking for a specific
server's performance data.
- PerfServlet response time: The PerfServlet responsiveness
depends on the following factors:
- Numbers of application servers that exist in the cell.
- Number of resources configured in the cell (including applications).
- PerfServlet alternative: If you are looking for an alternative
to using the PerfServlet to capture data programmatically, refer to
the Perf MBean programming interfaces documentation, which exists
in the Reference > Programming Interfaces > MBean interfaces section
of the WebSphere Application Server information center..
bprac
Starting with version 6.0, the
PerfServlet in WebSphere Application Server uses the JMX Perf MBean
interface to retrieve the PMI data and outputs an XML document that
uses the J2EE 1.4 Performance Data Framework to describe the statistics.
The PerfSerlvet in can also provide an output that is compatible with
the PerfServlet 5.0. To provide PerfServlet 5.0 compatible output
it uses the PMI client interface.
The performance servlet .ear
file PerfServletApp.ear is located in the WAS_HOME/installableApps directory,
where WAS_HOME is the installation path for WebSphere Application
Server.
Starting with version 6.1, you must
enable application security to get the PerfServlet working.