User manual 3COM SUPERSTACK 3 WEBCACHE 1000

[. . . ] SuperStack® 3 Webcache 1000 (3C16115) Webcache 3000 (3C16116) User Guide http://www. 3com. com/ Part No. DUA1611-5AAA02 Published May 2001 3Com Corporation 5400 Bayfront Plaza Santa Clara, California 95052-8145 Copyright © 2001, 3Com Technologies. No part of this documentation may be reproduced in any form or by any means or used to make any derivative work (such as translation, transformation, or adaptation) without written permission from 3Com Technologies. 3Com Technologies reserves the right to revise this documentation and to make changes in content from time to time without obligation on the part of 3Com Technologies to provide notification of such revision or change. [. . . ] A high hit rate indicates more efficient operation, as the Webcache is saving requests from being sent to the Web, which speeds up response time and reduces bandwidth use. The hit rate that the Webcache achieves is largely dependant upon: I How frequently the same request is made. The smaller the range of requests made, the more effective the Webache will be and the higher the hit rate will be. Whether the content provider on the origin web site allows the content to be cached or not. Some content providers will prevent certain information from being cached. If so, the copy held on the Webcache must be discarded, and the new version retrieved. This is treated as a cache miss. I I I Request Rate (sec-1) The average number per second of client machine HTTP requests sent to the Webcache. System Performance Graphs 89 I Hit and Miss Latencies (msec) The average time per request that the Webcache takes to respond to client machine HTTP requests. A short response time indicates more efficient operation, because more content is being served from the high speed Webcache, and less from the slow World Wide Web. I Throughput (Kbits/sec) The average amount per second of HTTP throughput served by the Webcache. System Performance Graphs The System Performance graphs show more detailed information about the performance of the Webcache. They are intended for use by your System Administrator and 3Com support personnel. Select one of the three available time periods, Daily, Weekly, or Monthly, by clicking the appropriate radio button. The System Performance graphs show the following information, which is updated every 5 minutes: I CPU Load (%) The average and maximum percentage of load on the Webcache's central processing unit (CPU). I Memory Usage (Mbytes) The average amount of physical memory that is being used in the Webcache. I/O Performance Graphs The I/O (Input/Output) Performance graphs show more detailed information about the performance of the Webcache. They are intended for use by your System Administrator and 3Com support personnel. 90 CHAPTER 9: PERFORMANCE MONITORING To view the I/O Performance graphs: 1 Log in to the Web interface. Select one of the three available time periods, Daily, Weekly, or Monthly, by clicking the appropriate radio button. The I/O Performance graphs show the following information, which is updated every 5 minutes: I Disk Activity (sec -1) The average number of disk operations per second to the caching disk(s). I Network Packets (sec -1) The average number per second of TCP packets sent to and received by the Webcache. I New TCP Connection (sec -1) The average number per second of TCP connections established by the Webcache. I DNS Lookups (sec -1) The average number per second of Domain Name System (DNS) server requests sent to the Webcache. I DNS Hit Rate (%) The average percentage of Domain Name System (DNS) server requests served by the Webcache. This is calculated as the ratio of host database hits to host database requests. The Webcache has its own internal cache of DNS entries. The DNS Hit Rate shows how effective this cache is being in avoiding DNS lookups to the DNS server. 10 SYSTEM DIAGNOSTICS This chapter contains information about troubleshooting the configuration and network connectivity of the Webcache 1000/3000. It covers the following topics: I I I I What are System Diagnostics?Pinging Other Devices Tracing IP Addresses System Log What are System Diagnostics? You can use the various system diagnostic capabilities of the Webcache to help you identify any problems that may occur. I I I Ping -- Ping other devices on the network. System Log -- View information about the Webcache. Pinging Other Devices The PING feature allows you to send out a PING request to test whether devices on an IP network are accessible and functioning correctly. This feature is useful to diagnose connectivity problems such as a failed network device between the Webcache and the web server being accessed. To ping a device using the Web interface: 1 Log in to the Web interface. The Ping/Traceroute screen is displayed. Performing a Ping 92 CHAPTER 10: SYSTEM DIAGNOSTICS 4 In the IP Address field, enter the IP address of the device that you want to PING. [. . . ] SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 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