Retry interval. which specifies the length of time to wait before
trying to connect to a server that has been marked temporarily unavailable. The
plug-in marks a server temporarily unavailable if the connection to
the server fails. Although a default value is 60 seconds, you might
have to lower this value in order to increase throughput under heavy
load conditions. Lowering the RetryInterval might help when the IBM
HTTP Server is configured to have fewer than 10 threads per process.
How
can lowering the RetryInterval affect throughput? If the plug-in attempts
to connect to a particular application server while the application
server threads are busy handling other connections, which happens
under heavy load conditions, the connection might time out, causing
the plug-in to mark the server temporarily unavailable. If the same
plug-in process has other connections open to the same server and
a response is received on one of these connections, the server is
marked again. If there are only a few threads per IBM HTTP Server
process, there might not be an established connection to this application
server . When this situation occurs, the plug-in must wait for the
entire retry interval.
Note: Although lowering the
RetryInterval can improve performance, if all the application servers
are running, a low value can have an adverse affect when one of the
application servers is down. In this case, each IBM HTTP Server process
attempts to connect and fail more frequently, resulting in increased
latency and decreased overall throughput.