Nutanix is an industry leader in hyper converged infrastructure and software defined storage that is optimized for virtual workloads. You can even think it as a cluster-in-a-box solution with compute, storage and hypervisor consolidated together into a 1U or 2U enclosure. And its interesting that in a Nutanix architecture there is no RAID and no need of a SAN storage too. Storage is totally local and they are using direct attached local disks (combination of both SSD and SAS disks) for storing data.
How does it look like ?
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| Front and rear side of a Nutanix appliance (eg : NX-1000) |
Each Nutanix box contains 4 independent nodes with are clustered together. This is shown in the figure below.
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| Nutanix box with 4 nodes |
Each of these nodes operate independently, it has its own CPU, RAM, HDDs etc and all those nodes are clustered together. so each time you want to increase the compute and storage capacity, you can add more boxes (with 1, 2 or 4 nodes depending on the need) to the cluster. Detailed logical architecture of a single node is given below.
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| Single Nutanix node architecture |
You can see in each node, there are SSDs as well as SAS HDDs for storage. And there is a controller VM, which is actually a virtual storage controller that runs on each and every node for improving scalability and resiliency while preventing performance bottlenecks. This controller VM is something like a VSA, but it does more than that. It is intelligent than a traditional VSA and is capable of functionalities like automated tiering, data locality, de-duplication etc and much more. All storage controllers in a cluster communicates with each other forming Nutanix distributed file system. For each read, there are 3 levels of cache. An in-memory cache within each node, then a hot tier (SSDs) and finally cold tier (SAS HDDs). Here the hypervisor communicates with the controller VM just like it would communicate to a physical storage controller. When a write operation happens, the VM will contact the virtual storage controller and then it is written first to the local SSDs. To ensure the protection data is then replicated to multiple nodes in the cluster, so that it is always available even if a node fails. We can have RF2 (2 way replication) or RF3 (3 way replication). It is an auto healing system, so that if a node fails and if it has only one copy of data left, then the system will automatically identify it using map reduce or those type of analytics and then it will be replicated to another nodes.
If you want to add more nodes, all you have to do is to connect it to the network and power it on, the system will be auto discovered using a auto discovery protocol which runs on top of IPV6. So its very easy to add a new node to a cluster. You can dynamically expand your cluster resources by adding more boxes without shutting down the cluster. Rolling upgrades can be done with out downtime by updating the controller VM one by one in a cluster. Now, each node is clustered at the Nutanix architecture level and you can cluster it at the hypervisor level too (say, VMware ESXI cluster using vCenter server) and providing a highly available web-scale hyper converged solution.
DELL and Nutanix partnered together and they have introduced DELL XC Series appliances optimized for virtual workloads.
References :
www.nutanix.com
