That covers redundancy in case of a network card or cable failure, but isn't what partitioning is about. Multiple NICs cannot prevent partitioning.<div><br></div><div>As an example, partitioning might happen when a network switch between two network segments fails so you have nodes A+B in segment 1 able to talk to each other but unable to talk to nodes C+D in segment 2, while C+D can talk to each other but not A+B.</div>
<div><br></div><div>Pacemaker/corosync contain a lot of algorithms to fence off partitions without quorum and can resort to things like STONITH if required to force a node to shutdown rather than risk it causing disruption to the cluster (for example if it tries to take over traffic to a virtual IP you could end up in a case where you have two servers sending ARP responses for the same IP).</div>
<div><br></div><div>-Steve</div><div><br></div><div><br><div><br><div class="gmail_quote">
On 10 February 2013 15:27, Eliot Gable <span dir="ltr"><<a href="mailto:egable+freeswitch@gmail.com" target="_blank">egable+freeswitch@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
You use multiple NICs in the systems and send heartbeats out all of<br>
them. There is no other way to do it. Two NICs are required, and 3 are<br>
recommended.<br>
<div><div><br>
<br>
On Sun, Feb 10, 2013 at 6:54 AM, Marcin Gozdalik <<a href="mailto:gozdal@gmail.com" target="_blank">gozdal@gmail.com</a>> wrote:<br>
> I wonder how do you handle network partition? Simply "knowing" which nodes<br>
> are up in a distributed system is hard enough and there is a reason why<br>
> solutions like pacemaker/corosync have years of development behind them.<br>
><br>
> W dniu niedziela, 10 lutego 2013 użytkownik Eliot Gable napisał:<br>
>><br>
>> The beauty of the module is that it will not require any 3rd party<br>
>> software to operate. I am designing it to run entirely in-memory using<br>
>> multi-cast events to communicate between cluster nodes. No external<br>
>> database will be required to enable the automatic fail over and call<br>
>> recovery.<br>
>><br>
>> If you have your customers / clients using DNS to point traffic to<br>
>> your system and you run multiple master nodes with DNS performing load<br>
>> balancing, you can also make use of the maintenance mode I have<br>
>> planned which will use a separate IP address and update your DNS<br>
>> records to remove the master which you put into maintenance mode and<br>
>> put in the maintenance IP which is assigned to the slave node which is<br>
>> being promoted as master. This allows calls to drain off the master<br>
>> while new calls come up on the slave, and then you can gracefully shut<br>
>> down the master when all calls are finished. Once you are done with<br>
>> maintenance, you simply bring it back online and it comes up as a<br>
>> slave or a master as needed (according to your configured master /<br>
>> slave ratio). The IP which it was using as a master node becomes the<br>
>> new designated maintenance IP. This is the only case where a 3rd party<br>
>> software package is required, and it is an optional feature.<br>
>><br>
>><br>
>> On Sat, Feb 9, 2013 at 6:49 PM, Gilad Abada <<a href="mailto:ga@steadfasttelecom.com" target="_blank">ga@steadfasttelecom.com</a>><br>
>> wrote:<br>
>> > Hey Eliot<br>
>> ><br>
>> > Sounds exciting. Which DB will you be using Postgres? I will try to<br>
>> > get my company to pitch in a few dollars.<br>
>> ><br>
>> > Sent from my mobile device.<br>
>> ><br>
>> > On Feb 9, 2013, at 12:11 PM, Eliot Gable <<a href="mailto:egable%2Bfreeswitch@gmail.com" target="_blank">egable+freeswitch@gmail.com</a>><br>
>> > wrote:<br>
>> ><br>
>> >> For the past two years, I have been working on and off on a high<br>
>> >> availability cluster module for FreeSWITCH. If you would like to see<br>
>> >> HA built into FreeSWITCH directly, instead of dealing with Pacemaker +<br>
>> >> Corosync or other 3rd party systems, please check out the module,<br>
>> >> voice your support, provide feedback and suggestions, and consider<br>
>> >> supporting it.<br>
>> >><br>
>> >> Some advantages over a 3rd party solution like Pacemaker include:<br>
>> >><br>
>> >> - Sub-second failure detection and response (meaning it can start<br>
>> >> recovering calls less than a second after a failure occurs)<br>
>> >> - Failure detection is built into FreeSWITCH so it can detect<br>
>> >> conditions which 3rd party modules cannot detect<br>
>> >> - One shared configuration file between all nodes (no per-node IP<br>
>> >> configuration required)<br>
>> >> - No fixed number of nodes<br>
>> >> - Graceful migration of calls with a maintenance mode (requires DNS)<br>
>> >><br>
>> >> These are just some of the benefits of building a FreeSWITCH-specific<br>
>> >> HA system. For additional details about the project, please visit:<br>
>> >><br>
>> >> <a href="http://wiki.freeswitch.org/wiki/Mod_ha_cluster" target="_blank">http://wiki.freeswitch.org/wiki/Mod_ha_cluster</a><br>
>> >><br>
>> >><br>
>> >> If you would like to see this project come to fruition, please<br>
>> >> consider financially supporting it through Kickstarter:<br>
>> >><br>
>> >><br>
>> >> <a href="http://www.kickstarter.com/projects/1175121367/high-availability-cluster-module-for-freeswitch" target="_blank">http://www.kickstarter.com/projects/1175121367/high-availability-cluster-module-for-freeswitch</a><br>
>> >><br>
>> >><br>
>> >><br>
>> >> Thanks in advance for anyone who contributes, either with just a<br>
>> >> shout-out, with feedback and/or suggestions, and especially to those<br>
>> >> who pledge some financial support.<br>
>> >><br>
>><br>
>> _________________________________________________________________________<br>
>> Professional FreeSWITCH Consulting Services:<br>
>> <a href="mailto:consulting@freeswitch.org" target="_blank">consulting@freeswitch.org</a><br>
>> <a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
>><br>
>> FreeSWITCH-powered IP PBX: The CudaTel Communication Server<br>
>> <a href="http://www.cudatel.com" target="_blank">http://www.cudatel.com</a><br>
>><br>
>> Official FreeSWITCH Sites<br>
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>><br>
>> FreeSWITCH-users mailing list<br>
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>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
><br>
><br>
><br>
> --<br>
> Marcin Gozdalik<br>
><br>
> _________________________________________________________________________<br>
> Professional FreeSWITCH Consulting Services:<br>
> <a href="mailto:consulting@freeswitch.org" target="_blank">consulting@freeswitch.org</a><br>
> <a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
><br>
> FreeSWITCH-powered IP PBX: The CudaTel Communication Server<br>
> <a href="http://www.cudatel.com" target="_blank">http://www.cudatel.com</a><br>
><br>
> Official FreeSWITCH Sites<br>
> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
> <a href="http://wiki.freeswitch.org" target="_blank">http://wiki.freeswitch.org</a><br>
> <a href="http://www.cluecon.com" target="_blank">http://www.cluecon.com</a><br>
><br>
> FreeSWITCH-users mailing list<br>
> <a href="mailto:FreeSWITCH-users@lists.freeswitch.org" target="_blank">FreeSWITCH-users@lists.freeswitch.org</a><br>
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><br>
<br>
<br>
<br>
--<br>
</div></div>Eliot Gable<br>
<br>
"We do not inherit the Earth from our ancestors: we borrow it from our<br>
children." ~David Brower<br>
<br>
"I decided the words were too conservative for me. We're not borrowing<br>
from our children, we're stealing from them--and it's not even<br>
considered to be a crime." ~David Brower<br>
<br>
"Esse oportet ut vivas, non vivere ut edas." (Thou shouldst eat to<br>
live; not live to eat.) ~Marcus Tullius Cicero<br>
<div><div><br>
_________________________________________________________________________<br>
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<a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
<br>
FreeSWITCH-powered IP PBX: The CudaTel Communication Server<br>
<a href="http://www.cudatel.com" target="_blank">http://www.cudatel.com</a><br>
<br>
Official FreeSWITCH Sites<br>
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</div></div></blockquote></div><br></div></div>