ISPPlanet Cache Review Series - Compaq TaskSmart

Defining Cache Services
The TaskSmart caches HTTP 1.0 and 1.1, plus FTP and Gopher when requested via HTTP in proxy mode. Chuawiwat believes the TaskSmart's file system kernel and cache-tuned Ethernet drivers lend themselves to caching streamed multi-media, planned for NICS version 2 later this year. The TaskSmart does not cache news.

		Clients and servers are selectively exempted from caching by configuring Exception IPs and Bypass lists (below). Unfortunately, we found content vended by the cache even when Exception/Bypass features were configured. Compaq reproduced our problem, then found that Novell knew Bypass and Exception IPs had been broken in NICS build 1.0.38 and fixed in build 1.1.10. This new NICS build is included in Compaq's 1.1 release, now in QA
TaskSmart caching services are configured through the Cache page (above). The Client Accelerator panel configures IP addresses and ports for forward and transparent proxies.

Reverse proxy is configured with the Web Server Accelerator panel. In reverse proxy mode, the TaskSmart listens to a virtual IP and distributes requests, round-robin, across a pool of back-end servers. Back-end servers share dynamic workload, the cache vends static content, and clients are insulated from single-server failure. We successfully tested this with a mix of cacheable and non-cacheable content originating from a pair of back-end servers. We found no visible interruption when each back-end server was taken off-line. If persistent connections are used, each client will tend to hit the same back-end server repeatedly.

The URL Filtering panel can be used to add subscription "web blocking" services from XSTOP or N2H2 or explicitly permit and deny selected URLs. We used the N2H2 Internet Content Filtering Service to test this TaskSmart feature. To add a service, enter login, password, configuration URL, and database download interval (monthly, weekly, daily). Deny access by setting a category's Threshold = True and Flag = RedList. Use Overrides to specify exceptions by URL pattern. For example, block access all sites in the "Jokes" category, but never deny Dilbert.

 

Introduction/Under the Hood	> Tuning Cache Behavior
Getting Started	NICS Monitoring
Where to Use the TaskSmart	Integrated Management
Configuring the TaskSmart <	Compaq Insight Manager
Defining Cache Services	Product Support/Final Thoughts