Can you add a different higher spec server to an existing S2D cluster?

[Jaan]

Hi all happy friday!

 

We're looking at going s2d next year with a 3 node cluster. assuming that goes to plan, and we've had it in use for x-years, can you just add a new, higher spec server to the cluster with it being hyper converged?

 

Does it just absorb the resources and storage and then balance accordingly?

 

Then retire the older node and repeat 2 more times.

 

My gut is saying, no. But how would you upgrade the cluster assuming the nodes are of age and being retired with newer hardware. Surely they just have to be equal or higher spec?

 

I can't find any info on having different spec machines in an existing s2d cluster. Only that they have to be identical when first creating the s2d cluster.

 

Anybody help? i don't have the ability to test this or know the answer.

 

cheers

Edited November 17, 2017 by Jaan

[KK20]

This is what kept me off S2D. What if I had hardware failure and needed to change the server in 3 years time? Do I need to migrate to a new cluster? Assuming new hardware joins the cluster, it may not LET you if the HW is different. Regular clusters can take different hardware (as long as the different CPU architecture is enabled) as we run a pair of R630 and an R610 in our cluster but as far as S2D goes Im not sure.

 

Even MS own documents now say "recommend" not "must" https://docs.microsoft.com/en-us/windows-server/storage/storage-spaces/add-nodes when adding more storage. And thinking logically, how do you ADD more storage to servers without downtime? Surely you would add storage to your servers a bit at a time thus keeping the cluster up?

 

But if you have multiple servers that have different specs, different drives and different configurations then I would guess you need to have your S2D within VMs https://blogs.msdn.microsoft.com/clustering/2015/05/27/testing-storage-spaces-direct-using-windows-server-2016-virtual-machines/ thus host your S2D infrastructure within VMs that are guests of dissimilar hardware hosts. That way the VMs are identical "hardware" as far as S2D goes. Need a new server? Add another host/guest to the S2D.

 

The other obvious answer was starwind vsan as you don't need similar hardware....

 

The more I looked into S2D the more I saw issues. With 2 nodes the redundancy is "icky" at best (2 drives or 1 server? That's not a lot for a whole array - and you would be saving little over a 2 node cluster with a cheap HBA SAN - say a dell 32xx) 3 isn't much better. Since we already had datacentre licensing for our hosts we simply went with a 3 node stretch cluster

Edited November 30, 2017 by KK20