<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Times New Roman; font-size: 12pt; color: #000000'>The dying VM will of course not send anything, it's dead. Your node, however, knows of all the links and monitors its processes has with other nodes. It will detect that it has lost contact with the other node and and then send the exit signals and monitor information to its local processes. This may take some time before it happens.<br><br>Robert<br><br><hr id="zwchr"><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Max Bourinov" <bourinov@gmail.com><br><b>To: </b>"Torben Hoffmann" <torben.lehoff@gmail.com><br><b>Cc: </b>"Erlang" <erlang-questions@erlang.org>, "Roberto Ostinelli" <roberto@widetag.com><br><b>Sent: </b>Saturday, 15 September, 2012 8:46:08 AM<br><b>Subject: </b>Re: [erlang-questions] Fishing for best practices: distributed twin processes!<br><br><div>I afraid that in same cases dying VM won't send anything. Additional technique that might help in this situation is a watchdog process, but it bring another level of abstraction/complexity.</div><div><br></div><div>In our project we also need to monitor distributed systems and we will implement watchdogs.<br><br>Sent from my iPad</div><div><br>On 15.09.2012, at 10:21, Torben Hoffmann <<a href="mailto:torben.lehoff@gmail.com" target="_blank">torben.lehoff@gmail.com</a>> wrote:<br><br></div><div></div><blockquote><div>
Hi Roberto,<br>
<br>
Try contacting Laura Castro from Uni of Coruña who presented at the
Erlang Workshop 2012 yesterday regarding handling of netsplits and
node crashes.<br>
Their team had to go through some investigations before they got the
resilience they had promised the customer! <br>
<br>
The big question for you will actually be what to do when the layers
thinks that the other node is down - will you assume a net split and
buffer communication (if that is feasible for your application)? Or
will you assume node down and do a major clean-up?<br>
<br>
Cheers,<br>
___<br>
/orben<br>
<br>
<br>
<div class="moz-cite-prefix">On 2012-09-15 03:46, Roberto Ostinelli
wrote:<br>
</div>
<blockquote cite="mid:CAM5fRypo52mv86Qd+q0JMNK1tki56OxEhP-G5AUaW8n7CcZEqQ@mail.gmail.com">hello Michael,
<div><br>
</div>
<div>you're assuming right (separate VM), I'm familiar with links
and monitors, thank you. However I doubt that any message is
sent from a dying process if the VM on which it runs actually
blows up. That was my point.</div>
<div><br>
</div>
<div>r.</div>
<div><br>
<br>
<div class="gmail_quote">On Fri, Sep 14, 2012 at 3:47 PM,
Michael Truog <span dir="ltr"><<a href="mailto:mjtruog@gmail.com" target="_blank">mjtruog@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div> Assuming you have the
2 layers in separate Erlang VMs. You can have the Erlang
VMs connected with distributed Erlang, and have the twin
processes monitoring each other. If you wanted a simple
process death if either died, you could consider using a
link instead of 2 monitors. However, that seems like the
simplest solution, to avoid unnecessary complexity. You
might find strangeness if you start not using the default
net tick time (i.e., with a process link inbetween nodes),
with distributed Erlang, but you probably know it is best
to not play with that.
<div>
<div class="h5"><br>
</div>
</div>
</div>
</blockquote>
</div>
</div>
<br>
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