That covers redundancy in case of a network card or cable failure, but isn't what partitioning is about. Multiple NICs cannot prevent partitioning. 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. 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). -Steve On 10 February 2013 15:27, Eliot Gable <egable+freeswitch@gmail.com> wrote:
You use multiple NICs in the systems and send heartbeats out all of them. There is no other way to do it. Two NICs are required, and 3 are recommended.
I wonder how do you handle network partition? Simply "knowing" which nodes are up in a distributed system is hard enough and there is a reason why solutions like pacemaker/corosync have years of development behind them.
W dniu niedziela, 10 lutego 2013 użytkownik Eliot Gable napisał:
The beauty of the module is that it will not require any 3rd party software to operate. I am designing it to run entirely in-memory using multi-cast events to communicate between cluster nodes. No external database will be required to enable the automatic fail over and call recovery.
If you have your customers / clients using DNS to point traffic to your system and you run multiple master nodes with DNS performing load balancing, you can also make use of the maintenance mode I have planned which will use a separate IP address and update your DNS records to remove the master which you put into maintenance mode and put in the maintenance IP which is assigned to the slave node which is being promoted as master. This allows calls to drain off the master while new calls come up on the slave, and then you can gracefully shut down the master when all calls are finished. Once you are done with maintenance, you simply bring it back online and it comes up as a slave or a master as needed (according to your configured master / slave ratio). The IP which it was using as a master node becomes the new designated maintenance IP. This is the only case where a 3rd party software package is required, and it is an optional feature.
On Sat, Feb 9, 2013 at 6:49 PM, Gilad Abada <ga@steadfasttelecom.com> wrote:
Hey Eliot
Sounds exciting. Which DB will you be using Postgres? I will try to get my company to pitch in a few dollars.
Sent from my mobile device.
On Feb 9, 2013, at 12:11 PM, Eliot Gable <egable+freeswitch@gmail.com
wrote:
For the past two years, I have been working on and off on a high availability cluster module for FreeSWITCH. If you would like to see HA built into FreeSWITCH directly, instead of dealing with Pacemaker
On Sun, Feb 10, 2013 at 6:54 AM, Marcin Gozdalik <gozdal@gmail.com> wrote: +
Corosync or other 3rd party systems, please check out the module, voice your support, provide feedback and suggestions, and consider supporting it.
Some advantages over a 3rd party solution like Pacemaker include:
- Sub-second failure detection and response (meaning it can start recovering calls less than a second after a failure occurs) - Failure detection is built into FreeSWITCH so it can detect conditions which 3rd party modules cannot detect - One shared configuration file between all nodes (no per-node IP configuration required) - No fixed number of nodes - Graceful migration of calls with a maintenance mode (requires DNS)
These are just some of the benefits of building a FreeSWITCH-specific HA system. For additional details about the project, please visit:
http://wiki.freeswitch.org/wiki/Mod_ha_cluster
If you would like to see this project come to fruition, please consider financially supporting it through Kickstarter:
http://www.kickstarter.com/projects/1175121367/high-availability-cluster-mod...
Thanks in advance for anyone who contributes, either with just a shout-out, with feedback and/or suggestions, and especially to those who pledge some financial support.
Professional FreeSWITCH Consulting Services: consulting@freeswitch.org http://www.freeswitchsolutions.com
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Official FreeSWITCH Sites http://www.freeswitch.org http://wiki.freeswitch.org http://www.cluecon.com
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-- Marcin Gozdalik
_________________________________________________________________________ Professional FreeSWITCH Consulting Services: consulting@freeswitch.org http://www.freeswitchsolutions.com
FreeSWITCH-powered IP PBX: The CudaTel Communication Server http://www.cudatel.com
Official FreeSWITCH Sites http://www.freeswitch.org http://wiki.freeswitch.org http://www.cluecon.com
FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org
-- Eliot Gable
"We do not inherit the Earth from our ancestors: we borrow it from our children." ~David Brower
"I decided the words were too conservative for me. We're not borrowing from our children, we're stealing from them--and it's not even considered to be a crime." ~David Brower
"Esse oportet ut vivas, non vivere ut edas." (Thou shouldst eat to live; not live to eat.) ~Marcus Tullius Cicero
_________________________________________________________________________ Professional FreeSWITCH Consulting Services: consulting@freeswitch.org http://www.freeswitchsolutions.com
FreeSWITCH-powered IP PBX: The CudaTel Communication Server http://www.cudatel.com
Official FreeSWITCH Sites http://www.freeswitch.org http://wiki.freeswitch.org http://www.cluecon.com
FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org