134 CHAPTER 13: PROBLEM SOLVING
Solving Webcache
Performance
Problems
The performance of the Webcache is poor
Check:
■ Whether any of the cache storage devices have failed. Examine the
front panel LEDs to ensure there are no faults found. If there are,
contact 3Com support personnel. As long as there is at least one
working cache storage device, the Webcache will operate as a cache,
but the failure of a cache storage device will degrade the performance
of the Webcache. If all cache storage devices have failed, the
Webcache will pass all requests through to the Web without
performing any caching.
■ The Caching Performance graphs in the Device View -> Performance
folder. Specifically check the Hit and Miss Rate graph. If the hit rate
percentage is low, save the system log onto another device in your
network. Then use a utility like Webtrends to analyze your web traffic
and see if a higher hit rate is expected.
■ Run a network performance test between your client machines and
your Webcache using the Ping command. Check that the response
time is reasonable.
■ Analyze your network to look for network errors.
■ If you are using Proxy Auto Configuration (PAC) files to configure
browsers, try setting the browser settings manually to avoid the
overhead of PAC files.
■ If you are using the Web Proxy Auto-Discovery (WPAD) protocol to
configure the browsers on client machines, try setting the browser
settings manually to avoid the overhead of the WPAD protocol.
■ The Webcache Domain Name Server configuration to check that it can
access the DNS server.
No Web sites can be accessed using the Webcache
Check the Webcache DNS and Default Router settings, and try to ping
these addresses from the Webcache.
Alternatively, if the Webcache is operating in transparent mode, it will not
service Web requests from browsers on client machines that are using the
Webcache as a proxy server. None of those client machines will be able to
access the Web. You must configure the browsers to use another proxy
server and bypass the Webcache, or configure the browsers so that they
are not operating in proxy mode.
