Explain the relationship between nodes, blocks and clusters
Node
- A physical server contained in a Nutanix block
- Model Comparison:
- 2 Node (6000/7000)
- 4 Node (1000/2000/3000/3050)
- Each node runs a hypervisor (ESXi/HV/KVM) + Nutanix CVM (Controller VM)
Block
- A set of Nutanix nodes contained in a single enclosure
- Uniform populated blocks recommended
- Prevents storage skew
- Ensures if block fails/maintenance needed, system can run without interruption
Cluster
A group of nodes contained in one or more Nutanix blocks
Node/Block/Rack Awareness
- Determines component/data placement
- DSF is node/block aware
- Node awareness is default
- Replicas are replicated to another node to protect against node failure
- Min. 3 blocks needed for block awareness
- Replicas are written to other blocks in cluster
- Provides data availability in case of block outage
- As of AOS 4.5, block awareness is best effort
- Increases to rack aware as cluster scales
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- Within block, PSU + fans are the only shared components
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- In event of block failure, block awareness maintained and re-replicated blocks are replicated to other blocks in cluster:
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