Microsoft Dynamics AX (Archived)

Dynamics AX 2012 Failover Clustering

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Posted on by Tiklu Ganguly

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Hi All,

As per my understanding AX 2012 supports two clustering modes.

1) Clustering with Dedicated Load balancer

2) Clustering without dedicated load balancer.

but both of them have one problem. Once the client does a handshake with one AOS if that particular AOS goes down the client would immediately crash as It would loose the connectivity. Is there a way where we can do the clustering where if one AOS goes down then the session of the client would immediately be shifted to (failover) the other active AOS?

Regards

Tiklu

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André Arnaud de Cal... 301,134 Super User 2025 Season 2 on at

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Hi Tiklu,

This is not possible. The AOS has all the details of the client connection and also has some caching/memory details. So even if the client searches for another AOS, it cannot continue properly.

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Tiklu Ganguly 302 on at

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Hi André,

So you mean even if I have an AOS cluster setup and the AOS I am connected to goes down - my AX client would 100% crash? This does not sound very appealing to me.

Regards

Tiklu

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Guy Terry 28,924 Moderator on at

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Crash? It would complain that the AOS was not available, and then close. But yes, it does this 100%.

Simply restarting the Client will cause it to connect to an AOS that is working, and the user could continue.

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Umesh Pandit 9,315 User Group Leader on at

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Hi Tiklu,

Few nice articles :

axwonders.blogspot.in/.../standalone-aos-and-aos-clusters.html

technet.microsoft.com/.../dd309717.aspx

dynamics-ax.blogspot.in/.../ax-2012-new-high-avalability-options.html

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Brandon Wiese 17,788 on at

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The connection between the client and AOS is highly stateful. The AOS "knows" quite a lot about the client that is lost when an AOS terminates or goes offline. Imagine for a moment if that would happen in the middle of a journal or other posting process, would you really expect another AOS to pick right up where the crashed AOS left off? The synchronization that would be required is insane. You have the same issue with any clustering technology, i.e. Hyper-V clustering where a host crashes and the VM's restart on another host since they can not "hop" if the host takes them down cold. If, on the other hand, state were completely maintained in a common storage medium, like Exchange or web servers storing session in a database, then all hosts have simultaneous access to it and resiliency is increased as a result.

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Tiklu Ganguly 302 on at

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Thanks a lot guys for your answers :)

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bankk 6,609 on at

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May I confirm what I think I'm reading? Clustering whether with or without load balancer in AX really has no failover functionality. In a two-AOS environment with clustered load balancing, if I were on AOS1 but AOS2 goes down I could likely be impacted as well. Looking at the client sessions form I'd see though my user session is logged into AOS1, I may have spawned off worker sessions which were assigned to AOS2.

Is there an option to truly separate sessions across a multi-AOS environment so user and worker sessions are kept on the same AOS? Thanks in advance.

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hoang.nguyen83 275 on at

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Hi all,

I am sorry to bring it up again but i am curious how DB server behave? I think DB server only deal with 01 AOS at the time (i am talking about we have 2 AOS server with 1 DB server)

regards,

Mark

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Vilmos Kintera 46,149 on at

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Please open a new thread for your question, since it is only loosely related to the original topic.

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