On Fri, 19 Jan 2001, [ks_c_5601-1987] Çã³²Á¶ wrote:
> I am testing with polygraph-2.5.4. With two pairs of
> polysrv-polyclt set, I ran 800 req/sec test. When I test the
> direct connection of polysrv and polyclt, the performance was
> good. But when the cache was used, there were several hundreds of
> errors per sec. in the polygraph. Those errors happened in fill
> phase. But In the top phase there was no errors. So It does not
> seem to be a problem of cache.
>
> ReportGen said following errors
>
> #errno count count% explanation
> 32 82 0.01 "Broken pipe"
> 54 405644 70.14 "Connection reset by peer"
> 60 3021 0.52 "Operation timed out"
> 61 11623 2.01 "Connection refused"
> 263 241 0.04 "premature end of msg body"
> 267 157731 27.27 "unsupported HTTP status code"
>
> Have anybody experienced similar problem?
> Please give me an advice.
I can see two distinct possibilities:
- The cache was not able to *fill* at the offered
rate, but was able to sustain peak rate of the
"normal" workload. Fill traffic is very different
from the traffic in main phases so the cache may
be able to survive one but not the other.
Suggestion: try reducing fill rate by 50% or more
without changing the peak rate.
- The same errors happen during the main phases, but
you thought they did not because Polygraph uses
exponential back-off algorithm to report errors on
the console.
Suggestion: use error graph (the last graph) in the
generated report to see if errors have indeed
disappeared; also look carefully at the console
output to see if the errors were there (but were
_reported_ less frequently).
HTH,
Alex.
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