A TCO Analysis of Pure FlashStack & Nutanix Enterprise Cloud

In helping to prepare this TCO with Steve Kaplan here at Nutanix, I’ll be honest and say I was a little surprised at the results.

The Nutanix Enterprise Cloud platform is the leading solution in the HCI space and it while it is aimed to deliver great business outcomes and minimise CAPEX,OPEX and TCO, the platform is not designed to be “cheap”.

Nutanix is more like the top of the range model from a car manufacturer with different customer requirements. Nutanix has options ranging from high end business critical application deployments to lower end products for ROBO, such as Nutanix Xpress model.

Steve and I agreed that our TCO report needed to give the benefit of the doubt to Pure Storage as we do not claim to be experts in their specific storage technology. We also decided that as experts in Nutanix Enterprise Cloud platform and employees of Nutanix, that we should minimize the potential for our biases towards Nutanix to come into play.

The way we tried to achieve the most unbiased view possible is to give no benefit of the doubt to the Nutanix Enterprise Cloud solution. While we both know the value that many of the Nutanix capabilities have (such as data reduction), we excluded these benefits and used configurations which could be argued at excessive/unnecessary such as vSphere or RF3 for data protection:

  1. No data reduction is assumed (Compression or Deduplication)
  2. No advantage for data locality in terms of reduced networking requirements or increased performance
  3. Only 20K IOPS @ 32K IO Size per All Flash Node
  4. Resiliency Factor 3 (RF3) for dual parity data protection which is the least capacity efficient configuration and therefore more hardware requirements.
  5. No Erasure Coding (EC-X) meaning higher overheads for data protection.
  6. The CVM is measured as an overhead with no performance advantage assumed (e.g.: Lower latency, Higher CPU efficiency from low latency, Data Locality etc)
  7. Using vSphere which means Nutanix cannot take advantage of AHV Turbo Mode for higher performance & lower overheads

On the other hand, the benefit of the doubt has been given to Pure Storage at every opportunity in this comparison including the following:

  1. 4:1 data reduction efficiency as claimed
  2. Only 2 x 10GB NICs required for VM and Storage traffic
  3. No dedicated FC switches or cables (same as Nutanix)
  4. 100% of claimed performance (IOPS capability) for M20,M50 and M70 models
  5. Zero cost for the project/change control/hands on work to swap Controllers as the solution scales
  6. IOPS based on the Pure Storage claimed average I/O size of 32K for all IO calculations

We invited DeepStorage and Vaughn Stewart of Pure Storage to discuss the TCO and help validate our assumptions, pricing, sizing and other details. Both parties declined.

Feedback/corrections regarding the Pure Storage sponsored Technical Report by DeepStorage was sent via Email, DeepStorage declined to discuss the issues and the report remains online with many factual errors and an array (pun intended) of misleading statements which I covered in detail in my Response to: DeepStorage.net Exploring the true cost of Converged vs Hyperconverged Infrastructure

It’s important to note that the Nutanix TCO report is based on the node configuration chosen by DeepStorage with only one difference: Nutanix sized for the same usable capacity, but went with an All Flash solution because comparing hybrid and all flash is apples and oranges and a pointless comparison.

With that said, the configuration DeepStorage chose does not reflect an optimally designed Nutanix solution. An optimally designed solution would likely result in fewer nodes by using 14c or 18c processors to match the high RAM configuration (512GB) and different (lower) capacity SSDs (such as 1.2TB or 1.6TB) which would deliver the same performance and still meet the capacity requirements which would result in a further advantage in both CAPEX, OPEX and TCO (Total Cost of Ownership).

The TCO shows that the CAPEX is typically in the favour of the Nutanix all flash solution. We have chosen to show the costs at different stages in scaling from 4 to 32 nodes – the same as the DeepStorage report. The FlashStack product had slightly lower CAPEX on a few occasions which is not surprising and also not something we tried to hide to make Nutanix always look cheaper.

One thing which was somewhat surprising is that even with the top of the range Pure M70 controllers and a relatively low IO per VM assumption of 250, above 24 nodes the Pure system could not support the required IOPS and an additional M20 needed to be added to the solution. What was not surprising is in the event an additional pair of controllers and SSD is added to the FlashStack solution, that the Nutanix solution had vastly lower CAPEX/OPEX and of course TCO. However, I wanted to show what the figures looked like if we assume IOPS was not a constraint for Pure FlashStack as could be the case in some customer environments as customer requirements vary.


What we see above is the difference in CAPEX is still just 14.0863% at 28 nodes and 13.1272% difference at 32 nodes in favor of Pure FlashStack.

The TCO, however, is still in favor of Nutanix at 28 nodes by 8.88229% and 9.70447% difference at 32 nodes.

If we talk about the system performance capabilities, the Nutanix platform is never constrained by IOPS due to the scale out architecture.

Based on Pure Storage advertised performance and a conservative 20K IOPS (@ 32K) per Nutanix node, we see (below) that Nutanix IO capability is always ahead of Pure FlashStack, with the exception of a 4 node solution based on our conservative IO assumptions. In the real world, even if Nutanix was only capable of 20K IOPS per node, the platform vastly exceeds the requirements in this example (and in my experience, in real world solutions) even at 4 node scale.


I’ve learned a lot, as well as re-validated some things I’ve previously discovered, from the exercise of contributing to this Total Cost of Ownership (TCO) analysis.

Some of the key conclusions are:

  1. In many real world scenarios, data reduction is not required to achieve a lower TCO than a competing product which leverages data reduction.
  2. Even the latest/greatest dual controller SANs still suffer the same problems of legacy storage when it comes to scaling to support capacity/IO requirements
  3. The ability to scale without rip/replace storage controllers greatly simplifies customers sizing
  4. Nutanix has a strong advantage in Power, Cooling, Rack Space and therefore helps avoid additional datacenter related costs.
  5. Even the top of the range All Flash array from arguably the top vendor in the market (Pure Storage) cannot match the performance (IOPS or throughput) of Nutanix.

The final point I would like to make is the biggest factor which dictates the cost of any platform, be it the CAPEX, OPEX or TCO is the requirements, constraints, risks and assumptions. Without these, and a detailed TCO any discussion of cost has no basis and should be disregarded.

In our TCO, we have detailed the requirements, which are in line with the DeepStorage report but go further to make a solution have context. The Nutanix TCO report covers the high level requirements and assumptions in the Use Case Descriptions.

Without further ado, here is the link to the Total Cost of Ownership comparison between Pure FlashStack and Nutanix Enterprise Cloud platform along with the analysis by Steve Kaplan.

The All-Flash Array (AFA) is Obsolete!

Over the last few years, I’ve had numerous customers ask about how Nutanix can support bare metal workloads. Up until recently, I haven’t had an answer the customers have wanted to hear.

As a result, some customers have been stuck using their exisiting SAN or worse still being forced to go out and buy a new SAN.

As a result many customers who have wanted to use or have already deployed hyperconverged infrastructure (HCI) for all other workloads are stuck managing an all flash array silo to service some bare metal workloads.

In June at .NEXT 2016, Nutanix announced Acropolis Block Services (ABS) which now allows bare metal workloads to be serviced by new or existing Nutanix clusters.


As Nutanix has both hybrid (SSD+SATA) and all-flash nodes, customers can chose the right node type/s for their workloads and present the storage externally for bare metal workloads while also supporting Virtual Machines and Acropolis File Services (AFS) and containers.

So why would anyone buy an all-flash array? Let’s discuss a few scenarios.

Scenario 1: Bare metal workloads

Firstly, what applications even need bare metal these days? This is an important question to ask yourself. Challenge the requirement for bare metal and see if the justifications are still valid and if so, has anything changed which would allow virtualization of the applications. But this is a topic for another post.

If a customer only needs new infrastructure for bare metal workloads, deploying Nutanix and ABS means they can start small and scale as required. This avoids one of the major pitfalls of having to size a monolithic centralised, dual controller storage array.

While some AFA vendors can/do allow for non-disruptive controller upgrades, it’s still not a very attractive proposition, nor is it quick or easy. and reduces resiliency during the process as one of two controllers are offline. Nutanix on the other hand performs one click rolling upgrades which mean the largest the cluster, the lower the impact of an upgrade as it is performed one node at a time without disruption and can also be done without risk of a subsequent failure taking storage offline.

If the environment will only ever be used for bare metal workloads, no problem. Acropolis Block Services offers all the advantages of an All Flash Array, with far superior flexibility, scalability and simplicity.


  1. Start small and scale granularly as required allowing customers to take advantage of newer CPU/RAM/Flash technologies more frequently
  2. Scale performance and capacity by adding node/s
  3. Scale capacity only with storage-only nodes (which come in all flash)
  4. Automatically scale multi-pathing as the cluster expands
  5. Solution can support future workloads including multiple hypervisors / VMs / file services & containers without creating a silo
  6. You can use Hybrid nodes to save cost while delivering All Flash performance for workloads which require it by using VM flash pinning which ensures all data is stored in flash and can be specified on a per disk basis.
  7. The same ability as an all flash array to only add compute nodes.


  1. Your all-flash array vendor reps will hound you.

Scenario 2: Mixed workloads inc VMs and bare metal

As with scenario 1, deploying Nutanix and ABS means customers can start small and scale as required. This again avoids the major pitfall of having to size a monolithic centralised, dual controller storage array and eliminates the need for separate environments.

Virtual machines can run on compute+storage nodes while bare metal workloads can have storage presented by all nodes within the cluster, including storage-only nodes. For those who are concerned about (potential but unlikely) noisy neighbour situations, specific nodes can also be specified while maintaining all the advantages of Nutanix one-click, non-disruptive upgrades.


  1. Start small and scale granularly as required allowing customers to take advantage of newer CPU/RAM/Flash technologies more frequently
  2. Scale performance and capacity by adding node/s
  3. Scale capacity only with storage-only nodes (which also come in all flash)
  4. Automatically scale multi-pathing for bare metal workloads as the cluster expands
  5. Solution can support future workloads including multiple Hypervisors / VMs / file services & containers without creating a silo.


  1. Your All-Flash array vendor reps will hound you.

What are the remaining advantages of using an all flash array?

In all seriousness, I can’t think of any but for fun let’s cover a few areas you can expect all-flash array vendors to argue.


Ah the age old appendage measuring contest. I have written about this topic many times, including in one of my most popular posts “Peak performances vs Real world performance“.

The fact is, every storage product has limits, even all-flash arrays and Nutanix. The major difference is that Nutanix limits are per cluster rather than per Dual Controller Pair, and Nutanix can continue to scale the number of nodes in a cluster and continue to increase performance. So if ultimate performance is actually required, Nutanix can continue to scale to meet any performance/capacity requirements.

In fact, with ABS the limit for performance is not even at the cluster layer as multiple clusters can provide storage to the same bare metal server/s while maintaining single pane of glass management through PRISM Central.

I recently completed some testing with where I demonstrated the performance advantage of storage only nodes for virtual machines as well as how storage-only nodes improve performance for bare metal servers using Acropolis Block Services which I will be publishing results for in the near future.

Data Reduction

Nutanix has had support for deduplication, compression for a long time and introduced Erasure Coding (EC-X) mid 2015. Each of these technologies are supported when using Acropolis Block Services (ABS).

As a result, when comparing data reduction with all-flash array vendors, while the implementation of these data reduction technologies varies between vendors, they all achieves similar data reduction ratios when applied to the same dataset.

Beware of some vendors who include things like backups in their deduplication or data reduction ratios, this is very misleading and most vendors have the same capabilities. For more information on this see: Deduplication ratios – What should be included in the reported ratio?


Here we should think about what are the age old problems are with centralized shared storage (like AFAs)? Things like choosing the right controllers and the fact when you add more capacity to the storage, you’re not (or at least rarely) scaling the controller/s at the same time come to mind immediately.

With Nutanix and Acropolis Block Services you can start your All Flash solution with three nodes which means a low capital expenditure (CAPEX) and then scale either linearly (with the same node types) or non-linearly (with mixed types or storage only nodes) as you need to without having to rip and replace (e.g.: SAN controller head swaps).

Starting small and scaling as required also allows you to take advantage of newer technologies such as newer Intel chipsets and NVMe/3D XPoint to get better value for your money.

Starting small and scaling as required also minimizes – if not eliminates – the risk of oversizing and avoids unnecessary operational expenses (OPEX) such as rack space, power, cooling. This also reduces supporting infrastructure requirements such as networking.


As shown below, the Nutanix Acropolis Distributed Storage Fabric (ADSF) can support almost any workload from VDI to mixed server workloads, file, block , big data, business critical applications such as SAP / Oracle / Exchange / SQL and bare metal workloads without creating silos with point solutions.


In addition to supporting all these workloads, Nutanix ADSF scalability both from a capacity/performance and resiliency perspective ensures customers can start small and scale when required to meet their exact business needs without the guesswork.

With these capabilities, the All-Flash array is obsolete.

I encourage everyone to share (constructively) your thoughts in the comments section.

Note: You must sign in to comment using WordPress, Facebook, LinkedIn or Twitter as Anonymous comments will not be approved,

Related Articles:

  1. Things to consider when choosing infrastructure.

  2. Scale out performance testing with Nutanix Storage Only Nodes

  3. What’s .NEXT 2016 – Acropolis Block Services (ABS)

  4. Scale out performance testing of bare metal workloads on Acropolis Block Services (Coming soon)

  5. What’s .NEXT 2016 – Any node can be storage only

  6. What’s .NEXT 2016 – All Flash Everywhere!

Problem: ROBO/Dark Site Management, Solution: XCP + AHV


Remote office / Branch Office commonly referred to as “ROBO” and dark sites (i.e.: offices without local support staff and/or network connectivity to a central datacenter) are notoriously difficult to design, deploy and manage.

Why have infrastructure at ROBO?

The reason customers have infrastructure at ROBO and/or Dark Sites is because these sites require services which cannot be provided centrally due to any number of constraints such as WAN bandwidth/latency/availability or, more frequently, security constraints.


Infrastructure at ROBO and/or dark sites need to be functional, highly available and performant without complexity. The problem is as the functional requirements of the ROBO/dark Sites are typically not dissimilar to the infrastructure in the datacenter/s, the complexity of these sites can be equal to the primary datacenter if not greater due to the reduced budgets for ROBOs.

This means in many cases the same management stack needs to be designed on a smaller scale, deployed and somehow managed at these remote/secure sites with minimal to no I.T presence onsite.

Alternatively, Management may be ran centrally but this can have its own challenges especially when WAN links are high latency/low bandwidth or unreliable/offline.

Typical ROBO deployment requirements.

Typical requirements are in many cases not dis-similar to those of the SMB or enterprise and include things like High Availability (HA) for VMs, so a minimum of 2 nodes and some shared storage. Customers also want to ensure ROBO sites can be centrally managed without deployment of complex tooling at each site.

ROBO and Dark Sites are also typically deployed because in the event of WAN connectivity loss, it is critical for the site to continue to function. As a result, it is also critical for the infrastructure to gracefully handle failures.

So let’s summarise typical ROBO requirements:

  • VM High Availability
  • Shared Storage
  • Be fully functional when WAN/MAN is down
  • Low/no touch from I.T
  • Backup/Recovery
  • Disaster Recovery


Nutanix Xtreme Computing Platform (XCP) including PRISM and Acropolis Hypervisor (AHV).

Now let’s dive into with XCP + PRISM + AHV is a great solution for ROBO.

A) Native Cross Hypervisor & Cloud Backup/Recovery & DR

Backup/Recovery and DR are not easy things to achieve or manage for ROBO deployments. Luckily these capabilities are built-in to Nutanix XCP. This includes the ability to take point in time application consistent snapshots and replicate those to local/remote XCP clusters & Cloud Providers (AWS/Azure). These snapshots can be considered backups once replicated to a 2nd location (ideally offsite) as well as be kept locally on primary storage for fast recovery.

ROBO VMs replicated to remote/central XCP deployments can be restored onto either ESXi or Hyper-V via the App Mobility Fabric (AMF) so running AHV at the ROBO has no impact on the ability to recover centrally if required.

This is just another way Nutanix is ensuring customer choice and proves the hypervisor is well and truely a commodity.

In addition XCP supports integration with the market leader in data protection, Commvault.

B) Built in Highly Available, Distributed Management and Monitoring

When running AHV, all XCP, PRISM and AHV management, monitoring and even the HTML 5 GUI are built in. The management stack requires no design, sizing, installation , scaling or 3rd party backend database products such as SQL/Oracle.

For those of you familiar with the VMware stack, XCP + AHV provides capabilities provided by vCenter, vCenter Heartbeat, vRealize Operations Manager, Web Client, vSphere Data Protection, vSphere Replication. And it does this in a highly available and distributed manner.

This means, in the event of a node failure, the management layer does not go down. If the Acropolis Master node goes down, the Master roles are simply taken over by an Acropolis Slave within the cluster.

As a result, the ROBO deployment management layer is self healing which dramatically reduces the complexity and and all but removes the requirement for onsite attendance by I.T.

C) Scalability and Flexibility

XCP with AHV ensures than even when ROBO deployments need to scale to meet compute or storage requirements, the platform does not need to be re-architected, engineered or optimised.

Adding a node is as simple as plugging it in, turning it on and the cluster can be expanded not disruptively via PRISM (locally or remotely) in just a few clicks.

When the equipment becomes end of life, XCP also allows nodes to be non-disruptively removed from clusters and new nodes added, which means after the initial deployment, ongoing hardware replacements can be done without major redesign/reconfiguration of the environment.

In fact, deployment of new nodes can be done by people onsite with minimal I.T knowledge and experience.

D) Built-in One Click Maintenance, Upgrades for the entire stack.

XCP supports one-click, non-disruptive upgrades of:

  • Acropolis Base Software (NDSF layer),
  • Hypervisor (agnostic)
  • Firmware
  • BIOS

This means there is no need for onsite I.T staff to perform these upgrades and XCP eliminates potential human error by fully automating the process. All upgrades are performed one node at a time and only started if the cluster is in a resilient state to ensure maximum uptime. Once one node is upgraded, it is validated as being successful (Similar to a Power on self test or POST) before the next node proceeds. In the event an upgrade fails, the cluster will remain online as I have described in this post.

These upgrades can also be done centrally via PRISM Central.

E) Full Self Healing Capabilities

As I have already touched on, XCP + AHV is a fully self healing platform. From the Storage (NDSF) layer to the virtualization layer (AHV) through to management (PRISM) the platform can fully self heal without any intevenston from I.T admins.

With Nutanix XCP you do not need expensive hardware support contracts or to worry about potential subsequent failures, because the system self heals and does not depend on hardware replacement as I have described in hardware support contracts & why 24×7 4 hour onsite should no longer be required.

Anyone who has ever managed a multi-site environment knows how much effort hardware replacement is, as well as the fact that replacements must be done in a timely manner which can delay other critical work. This is why Nutanix XCP is designed to be distributed and self healing as we want to reduce the workload for sysadmins.

F) Ease of Deployment

All of the above features and functionality can be quickly/easily deployed from out of the box to fully operational ready to run VMs in just minutes.

The Management/Monitoring solutions do not require detailed design (sizing/configuration) as they are all built in and they scale as nodes are added.

G) Reduced Total Cost of Ownership (TCO)

When it comes down to it, ROBO deployments can be critical to the success of a company and trying to do things “cheaper” rarely ends up actually being cheaper. Nutanix XCP may not be the cheapest (CAPEX) but we will be the lowest TCO which is after all what matters.

If you’re a sysadmin and you don’t think you can get any more efficient after reading the above than what you’re doing today, its because you already run XCP + AHV :)

In all seriousness, sysadmin’s should be innovating and providing value back to the business. If they are instead spending any significant time “keeping the lights on” for ROBO deployments then their valuable time is not being well utilised.


Nutanix XCP + AHV provides all the capabilities required for typical ROBO deployments while reducing the initial implementation and ongoing operational cost/complexity.

With Acropolis Operating System 4.6 and the cross hypervisor backup/recovery/DR capabilities thanks to the App Mobility Fabric (AMF), there is no need to be concerned about the underlying hypervisor as it has become a commodity.

AHV performance and availability is on par if not better than other hypervisors on the market as is clear from several points we have discussed.

Related Articles:

  1. Why Nutanix Acropolis hypervisor (AHV) is the next generation hypervisor
  2. Hardware support contracts & why 24×7 4 hour onsite should no longer be required.