Intel 1520 Transparency, Posting, Maintaining the cache: updates and feeds

Appendix A Caching Solutions and Performance 141

Two types of clusters are supported: soft clusters and management-only clusters.

A soft cluster consists of multiple appliances that use an external clustering

device such as an L4 Switch or router to handle load balancing and routing

responsibilities. A management-only cluster also consists of multiple appliances

whose functions are managed through a proprietary communications protocol

accessible through the Manager UI. A management-only cluster does not use an

external clustering device.

For more information about clustering, see Clustering‚ on page 144.

Transparency

The Intel NetStructure Cache Appliance can transparently intercept NNTP trafﬁc

bound for a well known NNTP server. By transparently intercepting, caching,

and serving the NNTP data from a centralized parent news server, the appliance

simpliﬁes migration and administration while both increasing responsiveness and

decreasing network use.

Posting

The Intel NetStructure Cache Appliance sends user article postings to the parent

news server. You can specify the parent news server that receives postings for a

particular group or set of groups from the command-line interface. For

procedural information, see Conﬁguring NNTP servers‚ on page 65. When acting

as the news server (accepting article feeds), the appliance accepts postings.

With background posting, the appliance queues posted articles until the posting

news server can accept the posted article.

Maintaining the cache: updates and feeds

The Intel NetStructure Cache Appliance can maintain the freshness of its cache

by:

✔Updating its cache on demand

✔Actively retrieving (pulling) updates at conﬁgured intervals

✔Accepting news feeds

You can conﬁgure the following options from both the Manager UI and the

command-line interface:

Pull the overview information for speciﬁed groups:

For all groups designated as pullover, the server will retrieve the overview

database information (using the OVER/XOVER commands) automatically and

periodically. Pulling overview information can be useful for high volume

groups that are frequently read but from which only a subset of the articles

are accessed.

Contents

Main Page Contents Page Page Page Page Page Page Page Preface Who should read this manual This manual uses the following conventions. Conventions used in this manual Chapter 1 Introduction Flexible cache architecture Why use this caching appliance? NetStructure What is an Intel Cache Appliance? Intel NetStructure Cache Appliance features Page How to use this guide Page Page Starting the system for the first time Page Page Page Accessing the Manager UI Page Page Using online help Accessing the command-line interface Verifying that caching works Changing passwords Page Chapter 3 Monitoring Appliance Performance Accessing monitor pages Using the Dashboard page Dashboard alert lights Resolving alarms Exposing node detail Changing the selected node Using the Node page Using the Graphs page Using the Protocols page Using the Cache page Using the ARM page Using the Other page Using the MRTG page Chapter 4 Configuring the Appliance Accessing configure pages Using the Server Basics page Setting general options Setting Web management options Setting virtual IP addressing options What are virtual IP addresses? Using virtual IP addressing for node failover Adding entries to the Virtual IP address list Setting browser auto configuration options Setting throttling of network connections Configuring load-shedding Enabling SNMP agents Using the Protocols page Configuring HTTP Configuring NNTP The following table describes the options. Page Configuring FTP The FTP section lets you congure FTP protocols. The following table describes the options. Using the Cache page Cache activation Storage The following table describes the storage options. The following table describes the freshness options. Freshness Variable content Using the Security page Using the Routing page Setting HTTP parent caching options Setting ICP options Establishing ICP peers Page Setting server accelerator options Checking transparency Checking WCCP Using the Host Database page Configuring the host database Page Configuring DNS Using the Snapshots page Page Chapter 5 Using the Command-Line Interface Starting the command-line interface Starting the appliance the first time Using the appliance after initial start-up Navigating the command-line interface Using the setup menu Changing network addresses configuration Changing the controller speed and transmission mode Changing the DNS address and domain name Changing the gateway address Configuring time zone settings Configuring date and time settings Viewing current network address settings Using the main menu Checking the status of the Server and Manager Starting the appliance Stopping the appliance Viewing and maintaining versions of the software Identifying which versions of the software are currently installed Installing a new version of the appliance software Application upgrade Patch upgrade OS/Application upgrade Running a different version of the appliance software Deleting a version of the appliance software Viewing which version of the appliance software is currently running Clearing statistics Rebooting the System Halting the System Changing the administrator password for telnet or serial access Resetting to factory settings Preparing a cache disk Using the config menu Setting general controls Configuring protocol options Configuring HTTP options Configuring NNTP options Page Page Page Page Page Page Configuring Secure Socket Layer (SSL) port Configuring FTP options Setting filter rules Page Setting remap rules Page Configuring the cache Enabling caching for different protocols Setting disk storage options Setting object freshness options The following table shows the options: Configuring caching rules Page Page Configuring security options Controlling client access to the appliance Controlling access to the Manager UI Configuring routing options Configuring and maintaining ICP peers Page Page Page Page Controlling parent proxy caching Page Page Configuring WCCP options Configuring the Adaptive Redirection Module (ARM) Enabling and disabling transparent redirection Configuring ARM bypass rules Page Configuring load-shedding options Configuring the host database options The following table describes the options: Configuring logging options Using the monitor menu Viewing Node statistics Viewing Protocol statistics Page Page The following table describes the statistics for the FTP protocol: Viewing Cache statistics screen. The following table describes the statistics. Viewing Other statistics the screen. The following table describes the statistics. Page Using the expert menu Using the save menu Using the load menu Using the logoff menu Chapter 6 Troubleshooting Problems Rebooting your system Rebooting your system from the CLI Page Page Appendix A Caching Solutions and Performance Web proxy caching A day in the life of a cache request Ensuring cached object freshness Revalidating objects HTTP object freshness tests Deciding whether to serve HTTP objects Configuring HTTP freshness options Configuring HTTP revalidation Configuring HTTP cachability Caching HTTP alternates To cache or not to cache? Transparent proxy caching Serving requests transparently Interception strategies Using a layer 4-aware switch to filter transparency requests Using a WCCP-enabled router for transparency Using policy-based routing to filter transparency requests ARM redirection Adaptive interception bypass Appliance adaptive bypass More about bypass rules Static and dynamic (adaptive) bypass Configuring bypass options Server acceleration Advantages of server acceleration How server acceleration works Retrieving requested documents Page Web server redirects Understanding server acceleration mapping rules Examples of rules and translations Page Understanding cache hierarchies HTTP cache hierarchies ICP cache hierarchies NNTP cache hierarchies News article caching The appliance as a news server The appliance as a caching proxy news server Supporting several parent news servers Blocking particular groups Clustering Transparency Posting Maintaining the cache: updates and feeds Configuring Access control Obeying NNTP control messages Client bandwidth throttling Carrier-class architecture Performance Page High-availability Alarms Virtual IP failover Load shedding Node fault tolerance Expansion capabilities Centralized administration Page Page Page HTML messages sent to clients Page Standard HTTP response messages Page Page Glossary Page Page Page Page Page Index