Hi Harry, Given the example you gave, I would give a slight advantage to the fewer larger systems. Others might have a different opinion. Also, in your example, your 2-node setup has more total cores and more total memory, so that adds to its advantage. These kinds of things are always tradeoffs, though, so I would think about the factors in the tradeoffs and your situation and go from there.
For resources, think about cores, memory, and disk I/O capacity (disk I/O is less of a factor for e-node hosts). Network capacity can also be a factor. While MarkLogic scales very well, there is some overhead in a cluster to adding more hosts, as each host has to communicate with each other host. Most of the time this will not be terribly significant, particularly with moderate sized clusters, but it does put more demands on your network. More hosts also gives you that many more machines to manage, which can be a factor. It also gives you some more levers for load balancing (which might be good or not, depending on the complexity of your environment). That is the way I would begin to think about it. -Danny From: [email protected] [mailto:[email protected]] On Behalf Of Harry Bakken Sent: Wednesday, June 29, 2011 12:27 PM To: General MarkLogic Developer Discussion Subject: [MarkLogic Dev General] E Node Cluster Question I am wondering if anyone can provide real world experience-based advice on clustering E nodes. Is it better for system performance to run with fewer beefy nodes or more not-so-beefy nodes? For example, would it be better to have: - two E Nodes built on 24 cores and 78 GB of RAM or - five E nodes with 8 cores and 16 GB of RAM Any insight or examples is appreciated. We have some internal info from other projects that give us some direction, but I am interested to know what others are doing and how MarkLogic is engineered for clustering. Is there a performance hit for more nodes? Does it really matter? Is it more a question of how much load there is to balance and hardware budget than system performance considerations? Thank you in advance, Harry
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