Best Hyper-Converged (HCI) Solutions

Hyper-converged is typically an "all in one box/rack" solution. It consists of compute, storage & network resources all tied together physically (and through software). 

Hyper-converged for a pro - is a complete solution. You don't have to architect it. All you have to know is how much "power" you need (what you want to do with it). While with converged infrastructure (which can still be 'software defined') you have to match and configure the components to work together. 

More often then not converged infrastructure is cheaper. You might already have the storage and networking resources, for example. And manufacturers put a premium on packaging the solution together. 

The key differences are scale, complexity and ease of use/management.  

Converged systems are more complex, assembled from multiple vendors using different management tools which allow systems to scale tremendously (Hundreds of servers and Multiple Peta-Bytes of Storage.  

Hyper-Converged systems are smaller, wrapped in a tight, easy to deploy shell that guides the user through system expansion, up to the nodal limits of ~32 servers.  Hyper-Converged systems rely on storage integrated into rack mount systems.  To assure stability, Hyper-Converged user choices are limited on storage and compute options.  These options have been well vetted and are fully supported by the HCI vendor.

Hyperconverged is a system cluster of at minimum 3 nodes. The system mirrors datas between nodes and runs virtual machines. 

Converged systems is anything between the classic server and hyperconverged platform. This converged concept was useful in waiting for hyperconverged development and should disappear in a near future.

converged infrastructure still incorporates hardware, running the technology natively on hardware. On the other hand, hype convergence is fully software-defined and completely integrated

Oh, you cant get rid of hardware in any way. (damn you Apple for auto-correcting english back to german).

But it is true that hci is a software defined approach which has the advantage of delivering new features without new hardware.

Another thing that destinguishes hyperconerged solutions from converged ones is the scale-out nature: simply add more nodes to the system to support new workloads without losing performance because you add all types at once (compute, storage and networking).

Cost metrics, Rob, Capex, and open savings and even a TCO should be accounted for.

1) Operational efficiency assumptions based on assessments. This should yield time to deploy, VM to admin ratios, device consolidation, and power usage.
2) My most important thing is in the Recovery Time Objective and how well does it sustain without data loss. Recovery Point Objective measures how far you can go back without loss and RTO is how long mission critical devices are brought back online.

Since you will find yourself managing VMs, you might consider a cost analysis there as well. (Remember you won't be managing devices any longer)

Your benefits in using an HCI is
1) A VM Centric Approach
2) A software-defined datacenter- ( less replacement, better utilization, pay as you go)
3) Data Protection
4) Lower costs
5) Centralized and even automated self-management tools.

For me an HCI solution should provide me:
- ease of management, 1 console does all, no experts needed, cloud Experience but with on-premise guarantees
- invisible IT, don't care about the underlying hardware, 1 stack
- built-in intelligence based on AI for monitoring and configuration
- guaranteed performance for any workloads, also when failures occur
- data efficiency with always-on dedupe and compression
- data protection including backup and restore
- scalability, ease of adding resources independent of each other (scale up & out)
- a single line of support

While there is a long list features/functions that we can look at for HCI -> In my experience of creating HCI solutions and selling it to multiple customers, here are some of the key things I have experienced most customers boil it down to:

1) Shrink the data center:
This is one of the key "Customer Pitch" that all the big giants have for you, "We will help you reduce the carbon footprint with Hyperconverged Infrastructure". It will be good to understand how much reduction they are helping you with. Can 10 racks come down to two, less or more? With many reduction technologies included and Compute + Storage residing in those nodes, what I mentioned above is possible, especially if you are sitting on a legacy infrastructure.

2) Ease of running it:
The other point of running and buying HCI is "Set it and forget it". Not only should you look at how easy it is for you to set up and install the system, but how long does it take to provision new VMs/Storage, etc. It is great to probe your vendors around to find out what they do about QOS, centralized policy management, etc. Remember that most HCI companies portfolios differ at the software layer and some of the features I mentioned above are bundled in their code and work differently with different vendors.

3) Performance:
This could be an architecture level difference. In the race of shrinking the hardware footprint down, you could face performance glitch. Here is an example: When you switch on de-duplication and compression, how much effect does it have on the overall performance on CPU, and thereby affecting the VMs. Ask your vendors how they deal with it. I know some of them out there offload such operations to a separate accelerator card

4) Scaling up + Scaling out:
How easy it is to add nodes, both for compute and storage?
How long does it take while adding nodes and is there a disruption in service?
What technologies do the vendors use to create a multi-site cluster? Keep in mind if the cluster is created with remote sites too?
Can you add "Storage only" or "Compute only" nodes if needed?
All of the above have cost implications in a longer run

5) No finger pointing:
Remember point number two? Most of these HCI are based on "Other Vendors' hardware" wrapping it with their own HCI Software and making it behave in a specific way. If something goes wrong, is your vendor okay to take full accountability and not ask you to speak with a hardware vendor? It will be a good idea to look for a vendor with a bigger customer base (not just for HCI but compute and storage in general) - making them a single point of contact and more resources to help you with, in case anything goes wrong.

In my opinion, the most important criteria when assessing HCI solutions other than the obvious performance. How does that HCI solution scale? Or in other words, how does one add storage and compute resources to the solution. Without understanding how the solution scales one can easily request resources without understanding how and why the overall costs have ballooned. The costs can balloon not only because you're adding additional nodes to your HCI cluster for the additional storage and compute resources that were needed but also with additional compute nodes added to the cluster this requires additional licensing for whichever hypervisor the HCI solution depends upon. This is usually on a per-compute-node basis. For example, some HCI architecture allows admins to add only storage to the HCI cluster when additional storage is needed. Not requiring the purchase of any additional licensing from the hypervisor's perspective. On the other hand, some HCI architecture requires you to add a compute node with the additional storage you need. Even if you don't need the compute resources required to add that storage. That compute node will then need to be properly licensed as well. This type of architecture can and usually does force its consumers to spend more money than the circumstances initially dictated. So for me how the HCI solution scales is most important because it can ultimately determine how cost-effective the HCI solution really is.

1）Easy to operate or not

2）Cost

3）Scaleable 

Absolutely the important aspects are:

1- Simplification, simple to implement, simple to manage and simple to use.

2- Reliability; There is always more reliability compared with a traditional solution.

For these two items when you see the cost, or better compare the TCO to a hyper-converged solution is always better.

HCI solutions have matured over time. While the swing in the global market is a yoyo between VxRail and Nutanix, there are quiet a few new vendors who have brought Hardware Agnostic solutions to the market. Management, ease of implementation was the key yesterday. Of late, I see a plethora of customers, who needs multi-cloud connectors available. Nutanix has taken a decent lead here, with the acquisition of Calm. Pricey though, a minimum pack with yearly subscription provides for 25VM's. VxRail from Dell EMC has a lot to catch up there, however with a free API connector to AWS, free for the first three TB, and then priced per TB of movement between private and public cloud. DISA STIG compliance is yet another point customers are interested to see in the solutions. Nutanix claims their code is built to comply with these rigorous standards for secure Virtualization layer with AFS, whereas Dell EMC offers scripts that have been pretested, to ensure the environment can comply to the standards.

Backup companies are vying to get their products certified. Wonder what Nutanix would have for the currently certified solutions, post their acquisition of "Mine". It still has miles to go.

Data protection is my primary concern, backup restore is a must have feature.

The more we try to define these items, the more variability to these definitions seems to exist. In a general sense, I like to classify as such:

"Converged" as infrastructure from one or more vendors that have a defined "cookbook" for integration of the systems to a simplified and supported platform for use.  These solutions help reduce the implementation and operational complexity and risks for the END CLIENT by providing a supported platform where the solution will work together, with known and pretested and qualified configurations.  These solutions can also, when multiple vendors are involved, simplify support options with a single support interface being provided by a vendor.  These solutions were among the first in the market where vendors were providing full stacks, and even multiple vendors provided stacks from which customers can build and utilize.

"Hyper-Converged" solutions attempt to increase the level of integration and simplification for the end client, and have TYPICALLY done so using the convergence of technology stacks such as storage arrays with compute platforms through software defines storage solutions. These solutions also will include a mandatory hypervisor for deployment - to allow the use of software-defined solutions to coexist on the platform.  This terminology is perhaps driven more by the different vendors, as a method to distinguish the software-defined platforms, and you can see a wide variety of solutions in this classification.   Cisco has Hyperflex, VMware have their various VSAN-enabled stacks, and Nutanix sells an HCI platform across multiple vendors. HP have defined a new "HCI" called a "dHCI" which appears to be a Converged Platform with various aspects of an HCI management plane.

In the end - worry less about the terminology used, and look to the value you get.  The costs will typically align with SIMPLE=expensive to buy, COMPLEX=expensive to operate....  find the place in the middle that works for your organization, and the level of capabilities you have and want to maintain in-house.   With the massive move to cloud technologies, infrastructure will quickly become a harder skill to find in young employees, but for the next decade, these issues will not be as prevalent.

As always - these are my own opinions, and your mileage may vary!

Well 99% of those terms are marketing. Typically when a vendor asks - are you converged or do you have a hyper-converged infrastructure it is about hardware. But you have it backwards. Typically HCI is a "packaged" solution. It is the compute, storage & networking in one "box" (or rack or whatever). It is not only designed to work together, it's sold that way. 

Converged infrastructure is more do-it-yourself. You pick and design the compute, the storage and the networking to work together, sort of best breed for the money. I know at least in small scales - like for small-medium businesses - HCI is typically much more expensive. At least that has been my experience. I can put together a better solution for less money. 

Both of these terms are almost exclusively used in the virtual machine world, doesn't apply to "traditional" data center. 

The other term that you will see used with these two terms is software defined data center. That's marketing speak for when you use virtual networking and storage - for example in the VMworld virtual switches with vSphere and NSX. Storage can be virtualized with VMware's VSAN product or 3rd party products like StarWind VSAN (that's what I use). 

To put this all in perspective from my perspective: I have a 3-node cluster made up of (3) HPE DL-380's, with 60 disks spread across those (3) nodes being managed and presented to VMware through StarWind VSAN. Inside VMware I have virtual distributed switches & virtual networks setup. Physically there are several network cards in each server - teamed - and going to the appropriate physical switches on the physical segments of the network. According to what we've said above that would be a "software defined data center" running in a converged infrastructure. Again, most of this is marketing speak but it does help to define what's going on.

A Converged Infrastructure has more hardware.  Compute is on one set of hardware.  Storage is on another set of direct-attached (or other) hardware.  Networking is separated, too.

In a Hyper-Converged Infrastructure, Compute and Storage are on the same hardware, and depending on the complexity of the solution, sometimes Networking isn't even needed because you can directly connect the nodes to each other if you only have 2 nodes.  Adding nodes is as simple as duplicating the hardware and scaling up or out, accordingly.   

A Hyper-Converged Infrastructure requires less hardware and gives you a more simplified solution.  It is also less expensive to procure, operate and maintain.   

Also in a converged infrastructure software is important. Converged for me is a combination of hardware components that are sold as a single solution and where a software layer is added to make the management easier. But the hardware solution consists mostly from individual server, storage and networking components.
Most hyperconverged solutions goes further with integrating the storage layer into the server layer, removing a layer of hardware, and where the software inside the solution create a shared storage pool for the server stack. Automatically the management layer is also simplified just as with the converged solution... Less hardware (or differently used) and more software inside... I call it more a typical evolution of IT infrastructure... Know that converged and hyperconverged is a marketing thing and not really a product as such... I saw converged and hyperconverged solutions already 20 years ago before it even existed... Just look for what you need and pick the right solution... 

(English version)

Converged infrastructure is basically a traditional infrastructure that has been preconfigured and integrated to ensure its functionality and accelerate its implementation.

Hyperconverged infrastructure is an infrastructure in which the computing, storage, and networking components are already virtualized and presented as clusters, allocating resources to each environment by the administrator without having to make changes to the physical hardware.

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(Original version)

La infraestructura convergente es básicamente una infraestructura tradicional que ha sido preconfigurada e integrada para asegurar su funcionalidad y acelerar su implementación.

La infraestructura hiperconvergente es una infraestructura en la que los componentes de procesamiento, almacenamiento y redes ya están virtualizados y se presentan como clústeres, asignando recursos a cada entorno por parte del administrador sin tener que realizar cambios en el hardware físico.

@Dan Reynolds gave a great answer.  

Most of it is marketing hype. So you have to dig in to the terms in every case to figure out what that term means to that vendor.  I think of it as "converged" is a virtualized solution with computing, storage, and networking on different hardware and "hyper-converged" is a virtualized solution with computing and storage (and possibly networking) on the same physical hardware.  

So if you have a hypervisor on a server with SAN storage on a different server, you're "converged", but if you put the SAN storage in the same server, you're "hyper-converged".  I actually try not to use the terms since they are ambiguous.

Yes, you are right, as converged system is mainly hardware-based and HCI is a software solution.

However, Converged System is preconfigured, prevalidated and certified solution for each application. And is available from HPE, Cisco, and other vendors. Converged System is a combination of compute, storage, networking and hypervisor. Also, you have a choice of vendors in a configuration like servers you can buy from HPE, networking you can buy from Cisco, etc.

Whereas HCI is a software-based solution in which each vendor has different solution like HPE Simplivity, Nutanix or vSAN, etc. HCI is combination of 4 or more technologies/products, like compute, storage, hypervisor and networking, in one solution. The choice of a converged system or HCI depends upon the application and customer choice. As there are many pros and cons for both the solutions.

Converged Architecture is a cohesive combination of hardware (compute, network and storage) and software (virtualisation, bare-metal OS) that is managed centrally but typlically at the element level.  This is avavailble as a turn-key solution from a single vendor or as a refernence architecture where the Customer has a greater responsibity in defining what they want.

Hyper-converged architecture is still managed centrally but through the virtualisation element only.  Compute and storage elements are typically consolidated with multiple units becoming the platform.  This consolidation simplifies the design/deployment but expansion of one element usually means the other may also be unnecessaily expanded.

A newer architecture dHCI (disaggregated HCI) separates the compute and storage reducing the expansion issues of the original HCI systems.

Converged Architecture is more flexible and less system resources are used in system operation whereas HCI is simpler to operate.

I would say, gather and understand the requirements, share and check with vendors, invite them for a solution with a POC on your environment, ask for use cases and for any legacy application/hardware, ask for the compatibility matrix, and then you will have the idea about the capabilities of that solution and vendor.

If you want to do a proof of concept about HCI, then I recommend that you do it and that you try all the hypervisors of your choice, with any of them you will find very good results.

Of course, performing a proof of concept in HCI equipment similar to your work load in production would be the best, as it has an almost real test.

In my case, I have migrated VMs that have databases like MSQL, postgres, mysql and in all of them I have better response times in read and write operations and zero data corruption.

The cloning of VM is very fast and the simplicity of the HCI operation helps me to concentrate on other activities.

The operation in HCI is very simple.

Selecting an HCI path is pretty straightforward and it goes through the cloud. You first select your workloads and what performance is needed for success. Since the key differentiation across HCI platforms today is software - you should be able to construct a target load of the apps you want to test and run them in a vendors cloud sandbox. You want to align your hardware solutions so you can leverage your existing support models and contracts, but you are testing software platforms for usability, performance and adaptability to your current operations model.

Once your workload homework is complete and your have selected an application type, VDI, OLTP, Data Warehouse etc, and determined worst case response times, you can throw a target workload to the cloud for evaluation. At this point you are looking for hiccups and deployment gotchas. HCI and cloud processes may be new to you - so you may need to stretch beyond your deployment models. This is a good thing. Recognize HCI is a leading edge trend and is one step removed from the cloud - which is where you will be in 5-10 years.

You want to look for key software features that lower the cost and complexity to manage this installation. But for a corner case or three, most applications will fit squarely in the middle of the "good" zone for today's SSD based HCI solutions.

With cloud testing of a target HCI platform you should learn how your applications perform, see key features you really really want and satisfy yourself that these systems can be managed without significant incremental effort by your current staff.

Then you do the grid - is the target aligned with my current hardware vendor; endorsements from people running similar applications; killer features and a drop dead signing bonus that justifies adding this platform to my portfolio of aging IT equipment? If and only If you come down to a near tie between two vendors should you go to the trouble of a full meal deal on-site PoC. They may not provide any more information than the version in the cloud, require physical hosting on your site, need an assigned project manager and then you get to deal with the loser - who may very well be your current vendor - and what a joy that will be.

There are several ways to evaluate HCI Solutions before buying, Customers need to contact HCI Vendors or one of the local resellers who propose the same technology.
Both of HCI Vendors and Resellers will be able to demonstrate the technology in Three Different scenarios like :

1 – Conduct Cloud-Based Demo, in which the presenter will illustrate product features and characteristics based on a ready-made environment and the presenter will be able to demonstrate also daily administration activities and reports as well.

2 – Conduct a Hosted POC, in which the presenter will work with the customer in building a dedicated environment for him and simulate his current infrastructure components.

3 – Conduct Live POC, in which the presenter has to ship appliances to customer’s data center and deploy the solution and migrate/create VMs for testing purpose and evaluate performance, manageability & Reporting.

If the vendor or a qualified reseller is doing the POC, there should be no mistakes because it’s a straightforward procedure.

Hi,

When evaluating HCI, it is absolutely essential to run a trial/POC to evaluate the system against candidate workloads it will be expected to run in production. However, there are quite a few things to watch out for. Here is a short list:

1. Remember that most HCI depend on a distributed architecture which means it is NOT the same as a standard storage array. What that means is that, if you want to do any performance benchmarking with tools such as IOMeter, you need to be extremely careful in the way you create your test VMs and how you provision disks. Guys such as Nutanix have their own tool X-Ray. However I would still stick to a more traditional approach.
2. Look at the list of apps you will be looking to run. If you are going to go for a KVM type of a hypervisor solution, you need to see if the apps are certified. More importantly, keep an eye out on OS certification. While HCI vendors will claim they will and can run anything and everything, you need the certification to come from the app/OS OEM.
3. Use industry standard benchmarking tools. Remember unless you are using a less “standard” type of a hypervisor such as KVM or Xen, you really don’t need to be wasting your time with the hypervisor part as VMWare is the same anywhere.
4. Your primary interest should be the storage layer without question and the distributed architecture. Remember with HCI, the computer does not change and hypervisor (assuming VMWare) does not change. What changes is the storage. Next there are the ancillary elements such as management and monitoring and other integration pieces. Look at these closely.
5. Use workload specific testing tools. Examples include LoginVSI, jMeter, Paessler/Bad boy for web server benchmarking etc.
6. Finally, remember to look at the best practices on a per-app basis. The reason I suggest this is because of the following. You may have been running an app like Oracle in your environment for ages in a monolithic way. However when you try the same app out in HCI it may not give you the performance you want. This has to do with the way the app has been configured/deployed. So looking at app best practices is something to note.
7. If you are looking at DR/backup etc, then evaluate your approaches. Are you using any native backup or replication capability or are you using any external tool. Evaluate these accordingly. Remember your RTO/RPO. Not all HCI will support sync replication.
8. Finally if you are looking at looking at native HCI capabilities around data efficiency etc (inline de-dupe and compression), you will need to design testing for these carefully.
9. Lastly, if you are looking at multiple HCI products, ensure you use a common approach across products. Otherwise your comparison will be like looking at oranges and apples.

Hope this helps.

Hi Nurit,

Some of the best POC that can be implemented and decide on if it suits our requirement is to take any of the below:

-VDI and Desktop-as-a-Service (DaaS)
-Test and Development
-Edge computing
-Cloud migration
-Backup and DR
-Logging and analytics



Mistakes to avoid (while doing a POC and taking the right call in deciding the right solution):
-Not giving storage enough consideration
-Misjudging network needs
-What to consider when scaling up
-Hard or soft HCI: Which to choose?
-Avoiding supplier lock-in
-Multiple suppliers and HCI
-Considering the whole SDDC stack

Hello,

VxRail team got a free lab environment to fully test their HCI solution. You may contact Dell or Dell partners in your area to have access.

When buying HCI, you need to accurately size the CPU, memory, and storage including future growth.

We found that a trial of Proxmox VE to deploy HCI is possible with 3-4 entry level server (we tried with our spare old server) which has been great for us to gain confidence on HCI setup and later plan accordingly for a full-fledged HCI setup.

Well, there are many things to consider, but I will start with scalability.

In HCI solutions scalability is achieved by adding nodes, while in dHCI (discrete HCI, hyper-converged solutions that use a SAN), you can expand the compute nodes or the storage. That means that dHCI is more flexible, and you will address your compute or storage needs in a tailored way.

The other thing to consider is availability.

HCI solutions base their availability in RAIN (Redundant Array of "inexpensive" Nodes). This means that you have more than one copy of your data located in different nodes. In case that you experience a failure in a node, your data is protected and accessible. Moreover, is extremely easy to set up a stretched cluster.

SAN-based architectures, usually include just one copy of your data, unless you use more than one storage system and a replication solution.

Another thing to consider is operations. HCI environments are easy to use, set up and scale. On the other hand, SAN-based solutions require more knowledge and maintenance efforts (Fabric OS's to update, HBAs, etc).

Whether to go 3 Tier (aka SAN) or HCI boils down to asking yourself what matters the most to you:

- Customization and tuning (SAN)
- Simplicity and ease of management (HCI)
- Single number to call support (HCI)
- Opex vs Capex
- Pay-as-you-grow (HCI)/scalability
- Budget cycles

If you are a company that only gets budget once every 4/5 years, and you can't get any capital expenditures for Storage/etc, pay-as-you-grow becomes less viable, and HCI is designed with that in mind. It doesn't rule out HCI, but it does reduce some of the value gained. Likewise, if you are on a budget cycle to replace storage and compute at different times, and have no means to repurpose them, HCI is a tougher sell to upper management. HCI requires you replace both at the same time, and sometimes budgets for capital don't work out.

There are also some workloads that will work better on a 3Tier solution vs HCI and vice versa. HCI works very well for anything but VMs with very large storage footprints. One of the key aspects of HCI performance is local reads and writes, a workload that is a single large VM will require essentially 2 full HCI nodes to run, and will require more storage than compute. Video workloads come to mind for this. Bodycams for police, surveillance cameras for businesses/schools, graphic editing. Those workloads can't reduce well, and are better suited for a SAN with very few features such as an HPE MSA.

HCI runs VDI exceptionally well, and nobody should ever do 3 Tier for VDI going forward. General server virtualization can realize the value of HCI, as it radically simplifies management.

3 Tier requires complex management and time, as you have to manage the storage, the storage fabric, and the hosts separately and with different toolsets. This also leads to support issues as you will frequently see the 3 vendor support teams blame each other. With HCI, you call a single number and they support everything. You can drastically reduce your opex with HCI by simplifiying support and management. If you're planning for growth up front, and cannot pay as you grow, 3 tier will probably be cheaper. HCI gives you the opportunity to not spend capital if you end up not meeting growth projections, and to grow past planned growth much easier as adding a node is much simpler than expanding storage/networking/compute independently.

In general, it's best to start with HCI and work to disqualify it rather than the other way around.

There are multiple factors that you shall be looking at while selecting one over the other.
1. Price- Price for HCI is cheaper if you are refreshing your complete infrastructure stack (Compute/Storage/network) however, if you are just buying individual components in the infrastructure such as compute or storage only, then 3-Tier infrastructure is cheaper.
2. Scalability-HCI is highly and easily scalable.
3. Support- On a 3 tier architecture, you have multiple vendors/departments to call/contact to get support on the solution. Whereas for HCI, you call/contact a single vendor addressing all your issues on the solution.
4. Infrastructure- For very small infrastructure, a 3Tier architecture based on iSCSI SAN can be a little cheaper. However, for a medium or large infrastructure HCI comes cheaper every time.
5. Workload type- If you are using VDI, I strongly recommend to use HCI. Similarly, for a passive secondary site, 3-tier could be OK. Please run all bench-marking tools to know what are your requirements.

I am sure HCI can do everything though.

There are so many variables to consider.

First of all, have in mind that tendency is not the rule, your needs should be the base of decision, so you don't have to choose HCI because it's the new kid on the block.

To start, think with your pocket, SAN is high cost if you are starting the infrastructure; cables, switches, and HBAs are the components to add to this structure that have a higher cost than traditional LAN components, On the other side, SAN requires more experimented experts to manage the connections and issues, but SAN has particular benefits sharing storage and servers functions like you can have on same SAN disk and backup and use special backup software and functionalities to move data between different storage components without direct impact on servers traffic.

SAN has some details to consider on cables like distance and speed, its critical the quality or purity to get the distance; the more distance, the less speed supported and transceiver cost can be the worst nightmare. But SAN have capabilities to connect storage boxes to hundreds of miles between them, LAN cables of HCI have 100 mts limit unless you consider a WAN to connect everything or repeaters or cascaded switches adding some risk element to this scenario.

Think about required capacities, do you need TB or PB?, Some dozens of TB can be fine on HCI, But if there are PBs you think on SAN, what about availability?, several and common nodes doing replication around the world but fulfilling the rules of latency can be considered with HCI, but, if you need the highest availability, replicating and high amount of data choose a SAN.
Speed, if it is a pain in the neck, LAN for HCI starts minimum at 10 Gb and can rise up to 100 Gb if you have the money, SAN has available just up to 32 Gb and your storage controller must be the same speed, this can drive the cost to the sky.

Scalability, HCI can have dozens of nodes replicating and adding capacity, performance, and availability around the world. With SAN storage you can have a limited number of replications between storage boxes, depending on manufactures normally you can have almost 4 copies of the same volume distributed around the world and scalability goes up to controllers limits its a scale-up model. HCI is a scale-out model to grow.

Functionalities, SAN storage can manage by hardware things like deduplication, compression, multiple kinds of traffic like files, blocks or objects, , on HCI just blocks and need extra hardware to accelerate some process like dedupe.

HCI is a way to share storage on LAN and have dependencies like the hypervisor and software or hardware accelerators, SAN is the way to share storage to servers, it is like a VIP lounge, so there are exclusive server visitors to share the buffet and can share the performance of hundreds of hard drives to support the most critical response times.

All depends of how you understand and use HCI:
If you see HCI as an integrated solution where storage is integrated into servers, and software-defined storage is used to create a shared pool of storage across compute nodes, performance will be the game changer of choosing for HCI or traditional SAN. The HCI solution of most vendors will be writing data 2 or 3 times for redundancy across compute nodes, and so where there is a performance impact on the applications due to the latency of the network between the nodes. Putting 25Gb networks, as some vendors recommend, is not always a solution since it is npt the bandwidth nut the latency of the network that defines the performance.

Low latency application requirements might push customers to traditional SAN in this case. If you use HCO for ease of management through a single pane of glass, I see many storage vendors delivering plugins to server and application software, eliminating the need of using the legacy SAN tools to create volumes and present them to the servers. Often it is possible to create a volume directly from within the hypervisor console and attach them to the hypervisor servers. So for this scenario, I don't see a reason choosing between the one or the other.

Today there is a vendor (HPE) that is combining traditional SAN in an HCI solution calling it dHCI. It gives you a HCI user experience, the independent scalability of storage and compute, and the low latency often required. After a time I expect other vendors will follow the same path delivering these kinds of solutions as well.

Maybe what I say becomes a little redundant.

As mentioned earlier, new technologies don't see why not use HCI.

I think it's an important factor and when you have a reduced team, you end up opting for a fully integrated solution.

HCI is wonderful, and possible to work with scalability, redundancy, there are tools to provide agile backup.

The traditional structure makes many analysts more comfortable, but for small teams it ends up overloading.

I use both frameworks, for large volatile data volume I believe that pure investment in HCI comes at a high cost, as it adds more storage host.

Also talk about abandoning the SAN you already have, in my opinion and something very drastic, each product has its strengths, replication for storage is still my favorite, even though there are very good replication solutions in HCI.

It's worth analyzing the whole, the size of the structure, the technical team, the qualifications, what kind of application you want to work on, the financial investment is important, but it can be more expensive in the end.

I've seen companies connecting their SAN to HCI, not always for performance reasons, but because it already exists, or there are low-cost solutions, and space requirements.

But when everything is new, it is possible to buy the minimum (HCI), already in SAN and I need to pre-dimension the number of ports, capacity, processing, speed, which will be used in its growth journey, this can make the project more expensive.

Business-wise, direct savings across the architecture, hardware, software, backup, and recovery, hyperconvergence can transform IT organizations from cost centers to frontline revenue drivers. A major issue in traditional IT architecture was that as complexity rises, the focus shifts from business problems to tech problems. The business’s focus should be on what IT can do for the bottom line, not what the bottom line can do for IT.

Capital expenditures (CAPEX): The one-time purchase and implementation expenses associated with the solution Operational expenditures (OPEX): The running costs of an IT solution – better known as the total cost of ownership (TCO) – that are incurred for managing, administering, and updating the existing IT infrastructure Considering the separate areas of cost reductions discussed above, organizations can evaluate the expense differentials between their traditional infrastructures and the HCI environment.

Hyperconvergence helps meet current and future needs, so it’s essential to calculate the TCO accurately. The TCO of a hyperconverged infrastructure includes annual maintenance fees for data centers and facilities, telecom services, hardware, software, cloud systems, and external vendors. Other costs include staff needed for deployment and maintenance, staff training and efforts to integrate with existing and legacy systems.

HCI overcomes the enormous wastage of resources and budgets common in the early phases of traditional infrastructure deployments because their scale dwarfs business needs at the time of purchase. HCI lends itself to incremental and granular scaling, allowing IT to add/remove resources as the business grows.

Scalability and agility are the main consideration factor to decide between SAN and HCI. SAN infra needs huge work involvement when attaining the end of support, end of life situation. Also, budgeting and procurement frequency plays a role.

Also, the limitation of HCI to be single datastore in VMware environment is a problem, when disk corruption or data corruption happens.