On Mon, 01 May 2006 00:26:05 CDT, Circuitsoft Development said: > Having done my own tests, I've determined that a 5msec timeout to > determine if a host has crashed would be appropriate. (My test was > basically looking at ping time over a saturated network - averaged > about 600 microseconds, topped at 3msec over 10 minutes) I figure that > 5msec timeout won't add any noticeable lag to the volume manager, as > most disk seek times are in that range.W Note that if you're setting 5ms as your timeout for detecting a *crash*, and your *ping* takes 3ms, that leaves you a whole whopping 2ms. If you have 1ms scheduler latency at *each* end (remember - you're in userspace at both ends, right?) you have approximately 0ms left for the remote end to actually *do* anything, and for the local end to process the reply. And if the remote end has to issue a syscall during processing the request, you're basically screwed. You need to be adding at least 1 zero to that timeout value.
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