Tag Archives: capacity

Nutanix NC2 – Direct to Cloud Value – Part 1

Posted on by
Reply

Nutanix “Cloud Clusters” a.k.a “NC2” was designed to enable customers to quickly and easily migrate from on premises environments into public cloud providers such as Amazon EC2 and Microsoft Azure and benefit from these offerings long list of business, architectural and technical advantages.

Two of the advantages which stand out to me are:

  1. Well understood standard architecture
  2. Global availability

The well understood architecture of both the Amazon and Azure offerings is incredibly valuable as organisations are largely protected from the underestimated cost & impact of “tribal knowledge” being lost with inevitable employee turnover.

The standard architecture is also highly valuable as both Microsoft and Amazon have extensive training and certification programmes to ensure customers can validate skills of potential employees and enable their existing staff.

The standard architecture also reduces many of the risks & cost of bespoke or custom designed environments where it’s almost impossible for customers (and even many vendors) to match the amount of architectural and engineering rigour as large companies such as Microsoft and Amazon can invest due to their incredible scale.

Now looking at the global availability of resources from both Amazon and Azure, this is extremely attractive as it enables customers to potentially deploy anywhere in the world and in a timely manner and reduce the risk of supply chain issues delaying projects and/or restoring resiliency to production environments after hardware failure/s.

Lets switch gears and look at NC2 and where it fits in.

For a long time now, I’ve be championing Nutanix HCI as the “standard platform for all workloads” as it allows customers to benefit from a well understood architecture which simplifies the traditional datacenter. This reduces the risks & cost of bespoke or custom designed environments and Nutanix training programmes ensure existing and future staff have or can develop the required skills.

However the problem with any on premises focused product/s are they’re all constrained by commercial challenges such as CAPEX, supply chain as well as organisational challenges such as change requests/approvals/windows and ultimately all of these negatively impact the time to value no matter how simple the deployment it’s once the equipment is delivered.

However with the introduction of NC2, customers benefit from the best of all worlds being Nutanix NC2 as the standard platform for all workloads which can be spanned from new/existing on premises deployments to public clouds providers such as Amazon and Azure.

Leveraging NC2 on Amazon and Azure effectively eliminates the commercial challenges (CAPEX & supply chain) and ensures the fastest possible time to value with new NC2 environments being able to be deployed in under 60 minutes. This partnership also enables customers have a true global reach available at their fingertips.

The ability to scale resources which provide increased performance & capacity to all workloads cluster wide) in minutes is also extremely valuable.

Summary

Nutanix NC2 provides a highly complimentary offering to AWS and Azure which enables customers to enjoy a simple, standard platform for all workloads across private and leveraging multiple public cloud providers and even operate across and migrate/failover between providers.

NC2 can also deliver higher performance, increased resiliency (business continuity) with lower risk, typically a lower total cost of ownership (TCO) while providing a genuine and relatively simple public cloud provider exit strategy.

In Part 2 we will dive into a detailed cost comparison of NC2.

Nutanix Scalability – Part 1 – Storage Capacity

Posted on by
Reply

It never ceases to amaze me that analysts as well as prospective/existing customers frequently are not aware of the storage scalability capabilities of the Nutanix platform.

When I joined back in 2013, a common complaint was that Nutanix had to scale in fixed building blocks of NX-3050 nodes with compute and storage regardless of what the actual requirement was.

Not long after that, Nutanix introduced the NX-1000 and NX-6000 series which had lower and higher CPU/RAM and storage capacity options which gave more flexibility, but still there were some use cases where Nutanix still had significant gaps.

In October 2013 I wrote a post titled “Scaling problems with traditional shared storage” which covers why simply adding shelves of SSD/HDD to a dual controller storage array does not scale an environment linearly, can significantly impact performance and add complexity.

At .NEXT 2015, Nutanix announced the ability to Scale Storage separately to Compute which allowed customers to scale capacity by adding similar to a shelf of drives like they could with their legacy SAN/NAS, but with the added advantage of having a storage controller (the Nutanix CVM) to add additional data services, performance and resiliency.

Storage only nodes are supported with any Hypervisor but the good news in they run on Nutanix’ Acropolis Hypervisor (AHV) which means no additional hypervisor licensing if you run VMware ESXi, and storage only nodes still support all the 1-click rolling upgrades so they add no additional management overhead.

Advantages of Storage Only Nodes:

  1. Ability to scale capacity seperate to CPU/RAM like a traditional disk shelf on a storage array
  2. Ability to start small and scale capacity if/when required, i.e.: No oversizing day 1
  3. No hypervisor licensing or additional management when scaling capacity
  4. Increased data services/resiliency/performance thanks to the Nutanix Controller VM (CVM)
  5. Ability to increase capacity for hot and cold data (i.e.: All Flash and Hybrid/Storage heavy)
  6. True Storage only nodes & the way data is distributed to them is unique to Nutanix

Example use cases for Storage Only Nodes

Example 1: Increasing capacity requirement:

MS Exchange Administrator: I’ve been told by the CEO to increase our mailbox limits from 1GB to 2GB but we don’t have enough capacity.

Nutanix: Let’s start small and add storage only nodes as the Nutanix cluster (storage pool) reaches 80% utilisation.

Example 2: Increasing flash capacity:

MS SQL DBA: We’re growing our mission critical database and now we’re hitting SATA for some day to day operations, we need more flash!

Nutanix: Let’s add some all flash storage only nodes.

Example 3: Increasing resiliency

CEO/CIO: We need to be able to tolerate failures and the infrastructure self heal but we have a secure facility which is difficult and time consuming to get access too, what can we do?

Nutanix: Let’s add some storage only nodes to ensure you have enough capacity (All Flash and/or Hybrid) to ensure sufficient capacity to tolerate “n” number of failures and rebuild the environment back to a fully resilient and performant state.

Example 4: Implementing Backup / Long Term Retention

CEO/CIO: We need to be able to keep 7 years of data for regulatory requirements and we need to be able to access it within 1hr.

Nutanix: We can either add storage only nodes to one or more existing clusters OR create a dedicated Backup/Retention cluster. Let’s start with enough capacity for Year 1, and then as capacity is required, add more storage only nodes as the cost per GB drops over time. Nutanix allows mixing of hardware generations so you’ll never be in a situation where you need to rip & replace.

Example 5: Supporting one or more Monster VMs

Server Administrator: We have one or more VMs with storage capacity requirements of 100TB each, but the largest Nutanix node we have only supports 20TB. What do we do?

Nutanix: The Distributed Storage Fabric (ADSF) allows a VMs data set to be distributed throughout a Nutanix cluster ensuring any storage requirement can be met. Adding storage only nodes will ensure sufficient capacity while adding resiliency/performance to all other VMs in the cluster. Cold data will be distributed throughout the cluster while frequently accessed data will remain local where possible within the local storage capacity on the node where the VM runs.

For more information on this use case see: What if my VMs storage exceeds the capacity of a Nutanix node?

Example 6: Performance for infrequently accessed data (cold data).

Server Administrator: We have always stored our cold data on SATA drives attached to our SAN because we have a lot of data and flash is expensive. One or twice a year we need to do a bulk read of our data for auditing/accounting purposes but it’s always been so slow. How can we solve this problem and give good performance while keeping costs down?

Nutanix: Hybrid Storage only nodes are a cost effective way to store cold data and combined with ADSF, Nutanix is able to deliver optimum read performance from SATA by reading from the replica (copy of data) with the lowest latency.

This means if a HDD or even a node is experiencing heavy load, ADSF will dynamically redirect Read I/O throughout the cluster to Deliver Increased Read Performance from SATA. This capability was released in 2015 and storage only nodes adding more spindles to a cluster is very complimentary to this capability.

Frequently asked questions (FAQ):

  1. How many storage only nodes can a single cluster support?
    1. There is no hard limit, typically cluster sizes are less than 64 nodes as it’s important to consider limiting the size of a single failure domain.
  2. How many Compute+Storage nodes are required to use Storage Only nodes?
    1. Two. This also allows N+1 failover for the nodes running VMs in the event a compute+storage node failed so VMs can be restarted. Technically, you can create a cluster with only storage only nodes.
  3. How does adding storage only node increase capacity for my monster VM?
    1. By distributing replicas of data throughout the cluster, thus freeing up local capacity for the running VM/s on the local node. Where a VMs storage requirement exceeds the local nodes capacity, storage only nodes add capacity and performance to the storage pool. Note: One VM even with only one monster vDisk can use the entire capacity of a Nutanix cluster without any special configuration.

Summary:

For many years Nutanix has supported and recommended the use of Storage only nodes to add capacity, performance and resiliency to Nutanix clusters.

Back to the Scalability, Resiliency and Performance Index.

Expanding Capacity on a Nutanix environment – Design Decisions

Posted on by
Reply

I recently saw an article about design decisions around expanding capacity for a HCI platform which went through the various considerations and made some recommendations on how to proceed in different situations.

While reading the article, it really made me think how much simpler this process is with Nutanix and how these types of areas are commonly overlooked when choosing a platform.

Let’s start with a few basics:

The Nutanix Acropolis Distributed Storage Fabric (ADSF) is made up of all the drives (SSD/SAS/SATA etc) in all nodes in the cluster. Data is written locally where the VM performing the write resides and replica’s are distributed based on numerous factors throughout the cluster. i.e.: No Pairing, HA pairs, preferred nodes etc.

In the event of a drive failure, regardless of what drive (SSD,SAS,SATA) fails, only that drive is impacted, not a disk group or RAID pack.

This is key as it limited the impact of the failure.

It is importaint to note, ADSF does not store large objects nor does the file system require tuning to stripe data across multiple drives/nodes. ADSF by default distributes the data (at a 1MB granularity) in the most efficient manner throughout the cluster while maintaining the hottest data locally to ensure the lowest overheads and highest performance read I/O.

Let’s go through a few scenarios, which apply to both All Flash and Hybrid environments.

  1. Expanding capacityWhen adding a node or nodes to an existing cluster, without moving any VMs, changing any configuration or making any design decisions, ADSF will proactively send replicas from write I/O to all nodes within the cluster, therefore improving performance while reactively performing disk balancing where a significant imbalance exists within a cluster.

    This might sound odd but with other HCI products new nodes are not used unless you change the stripe configuration or create new objects e.g.: VMDKs which means you can have lots of spare capacity in your cluster, but still experience an out of space condition.

    This is a great example of why ADSF has a major advantage especially when considering environments with large IO and/or capacity requirements.

    The node addition process only requires the administrator to enter the IP addresses and its basically a one click, capacity is available immediately and there is no mass movement of data. There is also no need to move data off and recreate disk groups or similar as these legacy concepts & complexities do not exist in ADSF.

    Nutanix is also the only platform to allow expanding of capacity via Storage Only nodes and supports VMs which have larger capacity requirements than a single node can provide. Both are supported out of the box with zero configuration required.

    Interestingly, adding storage only nodes also increases performance, resiliency for the entire cluster as well as the management stack including PRISM.

  2. Impact & implications to data reduction of adding new nodesWith ADSF, there are no considerations or implications. Data reduction is truely global throughout the cluster and regardless of hypervisor or if you’re adding Compute+Storage or Storage Only nodes, the benefits particularly of deduplication continue to benefit the environment.

    The net effect of adding more nodes is better performance, higher resiliency, faster rebuilds from drive/node failures and again with global deduplication, a higher chance of duplicate data being found and not stored unnecessarily on physical storage resulting in a better deduplication ratio.

    No matter what size node/s are added & no matter what Hypervisor, the benefits from data reduction features such as deduplication and compression work at a global level.

    What about Erasure Coding? Nutanix EC-X creates the most efficient stripe based on the cluster size, so if you start with a small 4 node cluster your stripe would be 2+1 and if you expand the cluster to 5 nodes, the stripe will automatically become 3+1 and if you expand further to 6 nodes or more, the stripe will become 4+1 which is currently the largest stripe supported.

  3. Drive FailuresIn the event of a drive failure (SSD/SAS or SATA) as mentioned earlier, only that drive is impacted. Therefore to restore resiliency, only the data on that drive needs to be repaired as opposed to something like an entire disk group being marked as offline.

    It’s crazy to think a single commodity drive failure in a HCI product could bring down an entire group of drives, causing a significant impact to the environment.

    With Nutanix, a rebuild is performed in a distributed manner throughout all nodes in the cluster, so the larger the cluster, the lower the per node impact and the faster the configured resiliency factor is restored to a fully resilient state.

At this point you’re probably asking, Are there any decisions to make?

When adding any node, compute+storage or storage only, ensure you consider what the impact of a failure of that node will be.

For example, if you add one 15TB storage only node to a cluster of nodes which are only 2TB usable, then you would need to ensure 15TB of available space to allow the cluster to fully self heal from the loss of the 15TB node. As such, I recommend ensuring your N+1 (or N+2) node/s are equal to the size of the largest node in the cluster from both a capacity, performance and CPU/RAM perspective.

So if your biggest node is an NX-8150 with 44c / 512GB RAM and 20TB usable, you should have an N+1 node of the same size to cover the worst case failure scenario of an NX-8150 failing OR have the equivalent available resources available within the cluster.

By following this one, simple rule, your cluster will always be able to fully self heal in the event of a failure and VMs will failover and be able to perform at comparable levels to before the failure.

Simple as that! No RAID, Disk group, deduplication, compression, failure, or rebuild considerations to worry about.

Summary:

The above are just a few examples of the advantages the Nutanix ADSF provides compared to other HCI products. The operational and architectural complexity of other products can lead to additional risk, inefficient use of infrastructure, misconfiguration and ultimately an environment which does not deliver the business outcome it was originally design to.