[Spread-users] mod_log_spread and RELIABLE_MESS
John David Duncan
jdd at greatschools.net
Wed Apr 3 17:48:16 EST 2002
> Daniel Rall wrote:
>> John David Duncan <jdd at greatschools.net> writes:
>>> So here's a simple question: is there any advantage in having
>>> mod_log_spread send messages as UNRELIABLE_MESS rather than
>> Indeed. Without flow control built in to the Spread server, the
>> "reliable" messages aren't nearly so reliable.
Well, there is certainly some flow control built into spread, and there
might not be any good way for mod_log_spread (as a sender) to implement
application-level flow control, because of the way apache processes come
My problem isn't that my logging machine can't keep up -- it's that the
slowest webserver/sender occasionally gets bogged down, and that this
effects the rest of the segment.
What I'm asking, since I don't need the semantics of reliable messages,
is whether it actually makes life any easier for spread if I send
> I have mod_log_spread logging fine in a decent size production cluster
> (4 million hits/day) and see almost no message loss on the Spread
> level, so even if I did change the RELIABLE_MESS to UNRELIABLE_MESS, I
> would have only lost a handful (<100) messages over the past week.
> If you are seeing message loss on the link layer or are overflowing
> your recv buffers, then you need to investigate the way you have Spread
> set up.
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