From: Michal Suchanek <hramrach@...>
Date: 2009-08-27T22:44:34+09:00
Subject: Re: DRb Mysterious Stops

2009/8/26 Darrin Thompson <darrinth@gmail.com>:
> Joel VanderWerf wrote:
>> It might help to add
>>
>> Thread.abort_on_exception = true
>>
>> in case a drb thread is dying silently. (DRb might be smarter than that,
>> though.)
>
> Tried that. No processes died or left any traces in my logs.
>
> What I did get was more consistent [bad] behavior, at least for today.
>
> It seems that any time my windows machine calls a method on my hosted
> suse9 64 bit machine, _and_ I return a large return value from that
> method, the conversation somehow gets "stuck". Large might be an array
> of 8000 lines of text from a file.
>
> I watched the conversation with wireshark and I saw that on one of my
> failures, right before everything hung, there were 15 tcp dup acks.

That many dup acks are somewhat suspicious but by themselves they
should not cause a lockup. If there is network problem the connection
should break eventually. However, some dumps of the part of the
conversation that causes excessive packet duplication might be useful.
Can you replicate the packet duplication with something simple like
scp file transfer or the like?

Are some of the earlier machines also 64bit?

I am not sure how 32bit vs 64bit integers work with marshalling. It
should work but perhaps some testing to ensure it really works well
would be a good idea.

Thanks

Michal