Troubleshooting a hierarchy configuration

Requests are not distributed as expected

The most likely causes of improper distribution of requests by your NetCache appliance are as follows:

You created a protocol-specific custom hierarchy rule but did not create a rule to handle the remainder of the traffic for that protocol.
NetCache provides protocol-specific hierarchy rules that are enabled according to the protocols you have specified that your hierarchy members handle. If you create a custom rule for a particular protocol, you must create a custom rule to handle the remainder of the requests for that protocol.
Hierarchy forwarding rules are not in the correct order.
The order of the rules is important because NetCache executes rules in the order in which they are listed in the hierarchy rules list, from top to bottom.

Requests for the local domain are not sent to local servers

The Local Domain rule controls whether requests for local servers are sent to the local servers. This rule is enabled when you select the Local Domain Enable check box on the Hierarchy - General page, which is associated with the "This Domain Is Local to This NetCache Appliance" option. Ensure that you have selected the Local Domain check box and that the local domain name is correct.

An exception to this guideline is if your local domain resides both inside and outside your firewall. You must create custom rules to handle this situation.

Requests for noncacheable objects are not handled

The NetCache default behavior is to send requests for noncacheable objects directly to origin servers. This cannot occur, however, unless your NetCache appliance has direct connectivity to the Internet. If your NetCache appliance does not have direct connectivity to the Internet, modify the noncacheable rule supplied by NetCache to send noncacheable object requests to another proxy-cache server that you have identified as a parent.

HTTP requests are not load balanced

If your log entries indicate that ICP is being used, the distribution method in the associated hierarchy forwarding rule is ICP rather than cluster. Load balancing occurs only if a hierarchy rule includes cluster as the distribution method.

If you have identified as neighbors any hierarchy members that handle HTTP, the distribution method in the HTTP-to-all rule supplied by NetCache was set to ICP. The reason is that NetCache always uses ICP to query neighbors.

Do not include neighbors as hierarchy members

Network Appliance recommends that you do not include neighbors as hierarchy members because of the overhead required by ICP communication. If no firewall exists and connectivity allows the specified neighbor to reach the Internet, you should identify that neighbor as a parent instead. If the neighbor does not have connectivity to the Internet, you should remove the neighbor from the hierarchy configuration and rely, instead, on parents to resolve requests.