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3node vxrail, 1 node failes, what happens to vm's running on that node ?
Hello,
Let's say a 3-node vxrail cluster and 1 node goes down....
What happens to vm's running on that node ?
Will they keep running ?
And what about the difference between VMware STD & ENT PLUS licenses ?
raju_allen
4 Posts
3
May 31st, 2018 02:00
3 Node VxRail cluster, it means VSAN cluster having 3 nodes.
By default, VSAN storage policy is RAID1, FTT=1 (failures to tolerate)
It means for a VM to be compliant, VM should have two mirror copies COPY1, COPY2, WITNESS
VSAN will decide the placement of these copies:
if there are only 3 nodes:
COPY1 on Host1
COPY2 on Host2
WITNESS on Host3
if one host failed, it still has more than 50% votes, so already powered on VM will keep running., VM storage policy compliance will be shown as non-compliant.
In 3 node cluster, if a host failed, VSAN will not have self-healing capability, meaning it cannot re-build the missing component on another host.
But when a host failed, and a customer wanted to create a new VM when there are only two hosts functioning, it will not be successful. because there is a host failed when you want to create a new VM, VSAN wanted to spread the copy1, copy2, witness to 3 hosts, when it searches for the 3rd host, it will not find, so VM cannot be created.
Hope this helps.
TomLambrechts
160 Posts
1
May 31st, 2018 06:00
Apparantly all VM's that were running on the failed node will have to be restarted by HA on another node.
So you'll have downtime, but no data loss.
Mike-Phoenix
3 Posts
0
January 2nd, 2024 20:33
Is a 3 node cluster really a 2 node cluster with an off cluster witness? I can find no documentation that supports the witness running on the same cluster as the hosts.
DELL-Naoyuki K
4 Operator
4 Operator
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January 17th, 2024 05:16
3 node cluster is the 3 node cluster. it's different from 2node + witness.