3Com SUPERSTACK 3 WEBCACHE 3000, Руководство пользователя

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222 C
HAPTER
14: P
ERFORMANCE
M
ONITORING
Webcache’s peak capacity — will normally improve the caching
behavior. However, a very low or zero request rate might indicate that
the Webcache is not receiving the requests correctly and furthermore
suggests that there is a problem with the setup and the deployment
mode.
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Hit and Miss Latencies
The average time per request in milliseconds that the Webcache takes
to respond to client machine HTTP requests. The response time graph
shows both cache hits and cache misses.
An average response time, normally less than 100 milliseconds,
indicates that the system is operating efficiently because more content
is being served from the high speed Webcache, and less from the slow
World Wide Web. If the response time is above-average, it may
indicate a higher proportion of revalidate hits that require contact with
the origin server, as shown on the Hit Rate graph in the Web Interface.
Very high hit response times that require several seconds or more
suggest that there may be a problem with the Webcache disk. If you
suspect this, check the Disk Status LEDs on the Webcache.
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Throughput
The amount of traffic in kilobits per second (Kbits/sec) between the
Webcache and its clients and also between the Webcache and the
Web servers.
1 Kbit/sec = 1,000 bps (bits per second)
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Client Connections
The number of TCP/IP connections currently open when the
Webcache plots a point on the graph. Each client will typically make
several connections to the Webcache when fetching a web page.
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Abort and Error Rate
The percentage of client connections that resulted in an error or were
aborted by client before the data was served. If the error rate is
greater than 30%, it may indicate that the Webcache has problems
communicating with the Web servers over the Internet. An abort rate
of over 30% is considered high and may indicate that clients consider
the performance too poor and subsequently abort the request to
download pages. If this happens, there may be a performance
problem with the Webcache.
Causes of aborts and errors include:
dua1611-5aaa04.book Page 222 Friday, November 29, 2002 8:56 PM