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Maximum node limit for a DMR cluster
Hi there, I want to know what is the limit of the maximum number of nodes in a DMR cluster (software event brokers)? I vaguely remember that the maximum is 15, but I'm not sure, and I can't find the documentation now, could anyone help me to find the answer?
Best Answer
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Think of it this way.
All nodes within a cluster must be fully meshed internal links.
All nodes on the other end of an external link is seen as one node, across one link. ie. each cluster is summarized behind the external link.So:
For picture 1. lets call the 3 clusters you have drawn as "TopLeft" TopRight" and "bottom". There are no transit clusters so you may need external link from "TopLeft" to "TopRight" if they need to talk to each other. Note that it is legal to spread the external links across nodes in a cluster to balance links.Each of the clusters have 5 nodes, they need to be fully meshed, you are missing links to the bottom node in each cluster. So within the cluster 4 nodes have 4 links and 1 node has 5 links,(one external). You could add 9 more nodes to each cluster then you would have 14 nodes with 13 links and 1 node with 14 links.
For picture 2. Same comments, you may need an external link from top to bottom if they need to communicate, and you need to full mesh within a cluster.
For picture 3. You have exceeded to link count, in this picture you can only have 14 nodes on each side of the external link.
2
![[Deleted User]](https://w4.vanillicon.com/v2/435b77851e3ea38c375fbec5b97e5800.svg)
Answers
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Hi. The 15 number you are thinking of is based on the current 14 link count max. So if you have one flat internal DMR link cluster it can have 15 nodes total, or if you have all external links you can have 15 "sites". This is generally not how Solace recommends building a mesh. The idea is to build internal DMR linked clusters in a site and then use external DMR links to join the sites together. Here is the documentation that describes this in a bit more detail. https://docs.solace.com/Configuring-and-Managing/DMR-Best-Practices.htm#DMR_Best_Practices
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Thank you very much for your reply, I probably understand what you are saying. But I still have some questions about the number of nodes, I drew three diagrams, according to what you said, pic_1(15 nodes total) the connection of this diagram should be allowed, right? Then I'm not sure if pic_2(20 nodes total) and pic_3(32 nodes total) are allowed.
Looking forward to your reply!pic_1(15 nodes total)
**pic_2(20 nodes total) **
**pic_3(32 nodes total) **
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Think of it this way.
All nodes within a cluster must be fully meshed internal links.
All nodes on the other end of an external link is seen as one node, across one link. ie. each cluster is summarized behind the external link.So:
For picture 1. lets call the 3 clusters you have drawn as "TopLeft" TopRight" and "bottom". There are no transit clusters so you may need external link from "TopLeft" to "TopRight" if they need to talk to each other. Note that it is legal to spread the external links across nodes in a cluster to balance links.Each of the clusters have 5 nodes, they need to be fully meshed, you are missing links to the bottom node in each cluster. So within the cluster 4 nodes have 4 links and 1 node has 5 links,(one external). You could add 9 more nodes to each cluster then you would have 14 nodes with 13 links and 1 node with 14 links.
For picture 2. Same comments, you may need an external link from top to bottom if they need to communicate, and you need to full mesh within a cluster.
For picture 3. You have exceeded to link count, in this picture you can only have 14 nodes on each side of the external link.
2
