lucasbernadsky
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Large scale cluster support

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Hi community. We are evaluating to deploy a 24 nodes vSAN 6.7 U3 Stretched cluster (12 + 12 +1). I'm aware of the 30 hosts limit (Stretched Clusters | VMware vSAN 6.7 Technical Overview | VMware ).

The question is, should we enable Large Cluster sopport for this scenario? This KB VMware Knowledge Base says that it's only for clusters with more than 32 hosts, but I couldn't find any info about Stretched Clusters.

Thanks!

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TheBobkin
VMware Employee
VMware Employee

Hello Lucas,

No, you shouldn't need to in this scenario - one of the main points of enabling this is increasing the /Net/TcpipHeapMax values to allow for the (potentially per node) greater amount of inter-node traffic and some other tweaks contained in /VSAN/goto11 - increased heap allocations and/or memory reservations (generally) don't come at zero-cost, if these are used and/or reserved they use system memory so I wouldn't advise setting them unless required:

VMware Knowledge Base

As an aside (and to expound on the storagehub article you referenced), It used to be 15 per site max (e.g. 15+15+1) but now allows for asymmetric configurations e.g. 20+10+1, but yes still capped at 30 nodes as you said.

Bob

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TheBobkin
VMware Employee
VMware Employee

Hello Lucas,

No, you shouldn't need to in this scenario - one of the main points of enabling this is increasing the /Net/TcpipHeapMax values to allow for the (potentially per node) greater amount of inter-node traffic and some other tweaks contained in /VSAN/goto11 - increased heap allocations and/or memory reservations (generally) don't come at zero-cost, if these are used and/or reserved they use system memory so I wouldn't advise setting them unless required:

VMware Knowledge Base

As an aside (and to expound on the storagehub article you referenced), It used to be 15 per site max (e.g. 15+15+1) but now allows for asymmetric configurations e.g. 20+10+1, but yes still capped at 30 nodes as you said.

Bob

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lucasbernadsky
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Thanks bob! You made it crystal clear for me

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