Category Archives: Business Critical Applications

Think HCI is not an ideal way to run your mission-critical x86 workloads? Think again! – Part 1

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I recently wrote a post called Fight the FUD: Nutanix scale limitations which corrected some mis-information VCE COO Todd Pavone has stated in this article COO: VCE converged infrastructure not affected by Dell-EMC about Nutanix scalability.

In the same interview, Todd makes several comments ( see quote below) which I can only trust to be accurate for VSPEX Blue but as he refers more generally about Hyper-converged systems, I have to disagree with many of the comments from a Nutanix perspective, and thought it would be good to discuss where I see Nutanix.

Where does VSPEX Blue fit into the portfolio?

Hyper-converged by definition is where you use software to find technology to manage what people like to call a commoditized infrastructure, where there is no external storage. So, the intelligence is in the software, and you don’t require the intelligence in the infrastructure. In the market, everyone has had an appliance, which is just a server with embedded storage or some marketed software, and ideal for edge locations or for single use cases. But you’re not going to put SAP and run your mission-critical business on an appliance. They have scaling challenges, right? You get to a certain number of nodes, and then the performance degrades; you have to then create another cluster, another cluster. It’s just not an ideal way to go run your mission-critical x86 workloads. [It’s] good for an edge, good for a simple form factors, good for single use cases or what I’ll call more simplified workloads.

In this post I will be specifically discussing Nutanix HCI solution, and while I have experience with and opinions about other products in the market, I will let other vendors speak for themselves.

The following quotes are not in the order Todd mentioned them in the above interview, they have been grouped together/ordered to avoid overlap/repeating comments and to make this blog flow better (hopefully). As such, if any comments appear to be taken out of context, it is not my intention.

So let’s break down what Todd has said:

  • Todd: In the market, everyone has had an appliance, which is just a server with embedded storage or some marketed software, and ideal for edge locations or for single use cases.

I agree that Hyper-converged systems such as Nutanix run on commodity servers with embedded storage. I also agree Nutanix is ideal for edge locations and can be successfully used for single use cases, but as my next response will show, I strongly disagree with any implication that Nutanix (as the markets most innovative leader in HCI, source: Gartner with 52% market share according to IDC) is limited to edge or single use cases.

  • Todd: “It’s just not an ideal way to go run your mission-critical x86 workloads” & “But you’re not going to put SAP and run your mission-critical business on an appliance.”

Interestingly, Nutanix is the only certified HCI platform for SAP.

As an architect, when designing for mission critical workloads, I want a platform which can/is:

a) Start small and scale as required (for example as vBCA’s demands increase)
b) Highly resilient & have automated self healing
c) Fully automated non-disruptive (and low impact) maintenance
d) Easy to manage / scale
e) Deliver the required levels of performance

In addition to the above, the fewer dependancies the better, as there is less to go wrong, troubleshoot, create bottlenecks and so on.

Nutanix HCI delivers all of the above, so why wouldn’t you run vBCA on Nutanix? In fact, the question I would ask is, “Why would you run vBCA on legacy 3 tier platforms”!

With legacy 3 tier in my experience it’s more difficult to start small and scale, typically 3-tier solutions have only two controllers which cannot self heal in the event of a failure, have complex and time consuming patching/upgrading procedures, typically have multiple points of Management (not single pane of glass like Nutanix w/ Acropolis Hypervisor), are typically much more difficult to scale (and require rip/replace).

The only thing most monolithic 3-tier products provide (if architected correctly) is reasonable performance.

Here is a typical example of a Nutanix customer upgrade experience compared to a legacy 3-tier product.

HdexTweetUpgrades

Think the above isn’t a fair comparison? I agree! Nutanix vs Legacy is no contest.

When I joined Nutanix in 2013, I was immediately involved with testing of mission critical workloads & I have no problems saying performance was not good enough for some workloads. Since then Nutanix has focused on building out a large team (3 of which are VCDX with years of vBCA experience) focusing on business critical applications, now applications like SQL, Oracle (including RAC deployments), MS Exchange and SAP are becoming common workloads for our customers who originally started with Test/Dev or VDI.

Think of Nutanix like VMware in 2005, everyone was concerned about performance, resiliency and didn’t run business critical applications on VI3 (later renamed vSphere), but over time everyone (including myself) learned virtualization was infact not only suitable for vBCA it’s an ideal platform. I’m here to tell everyone, don’t make the same mistake (we all did with virtualization) and assume Nutanix isn’t suitable for vBCA and wait 5 years to realise the value. Nutanix is more than ready (and has been for a while) for Mission critical applications.

Regarding Todd’s second statement “But you’re not going to put SAP and run your mission-critical business on an appliance.”

If not on an appliance, then what are we supposed to put mission-critical application on? Regardless of what you think of traditional Converged products, the fact is they are actually just a single SKU for multiple different pre-existing products (generally from multiple different vendors) which have been pre-architected and configured. They are not radically different and nor do they eliminate ongoing operational complexity which is a strength of HCI solutions such as Nutanix.

If anything putting mission critical applications on a simple and highly performant/scalable HCI appliance based solution (especially Nutanix) makes more sense than Converged / 3 Tier products. Nutanix is no longer the new kid on the block, Nutanix is well proven across all industries and on different workloads, including mission critical. Hell, most US Federal agencies including the Pentagon uses Nutanix, how much more critical do you want?  (Also anyone saying VDI isn’t mission critical has rock’s in their head! Think if all your users are offline, how productive is your company and how much use are all your servers?)

Imagine if the sizing of a traditional converged solution is wrong, or a mission critical application outgrows it before its scheduled end of life. Well with Nutanix, add one or more nodes (no rip and replace) and vMotion the workload/s, and you’ve scaled completely non disruptively. In fact, with Nutanix you should intentionally start small and scale as close to a just in time fashion as possible so your mission-critical application can take advantage of newer HW over the 3-5 years! Lower CAPEX and better long term performance, sounds like a WIN/WIN to me!

Even if it were true that Converged (or any other product) had higher peak performance (which in the real world has minimal value) than a Nutanix HCI solution, so what? Do you really want to have point solutions (a.k.a Silos) for every different workload? No. I wrote the following post which covers things to consider when choosing infrastructure which covers why you want to avoid silos which I encourage you to read when considering any new infrastructure.

  • Todd: They have scaling challenges, right? You get to a certain number of nodes, and then the performance degrades; you have to then create another cluster, another cluster.”

My previous post Fight the FUD: Nutanix scale limitations covers this FUD off in detail. In short, Nutanix has proven numerous times we can scale linearly, see Scaling to 1 Million IOPS and beyond linearly! for an example (And this video is from October 2013). Note: Ignore the actual IO number, the importaint factor is the linear scalability, not the peak benchmark number which have little value in the real world as I discuss here: “Peak Performance vs Real World Performance”.

  • Todd:  [It’s] good for an edge, good for a simple form factors, good for single use cases or what I’ll call more simplified workloads.

To be honest i’m not sure what he means by “good for a simple form factors”, but I can only assume he is talking about how HCI solutions like Nutanix has compact 4 node per 2RU form factors and use less rack space, power, cooling etc?

As for single use cases, I recommend customers run mixed workloads for several reasons. Firstly, Nutanix is a truly distributed solution which means the more nodes in a cluster, the more performant & resilient the cluster becomes. Scaling out a cluster also helps eliminate silos which reduces waste.

I recently wrote this post: Heterogeneous Nutanix Clusters Advantages & Considerations which covers how mixing node types works in a Nutanix environment. The Nutanix Distributed Storage fabric has lots of back end optimisations (ran by curator) which have been developed over the years to ensure heterogeneous clusters perform well. This is an example of technology which marketing slides can’t represent the value of, but the real world value is huge.

I have been involved with numerous mission critical application deployments, and there are heaps of case studies available on the Nutanix website for these deployments available at http://www.nutanix.com/resources/case-studies/.

A final thought for Part 1, with Nutanix, you can build what you need today and have mission critical workloads benefit from latest generation HW on a frequent basis (e.g.: Annually) by adding new nodes over time and simply vMotioning mission critical VMs to the newer nodes. So over say a 5 year life span of infrastructure, your mission critical applications could benefit from the performance improvements of 5 generations of intel chipsets not to mention the ever increasing efficiency of the Nutanix Acropolis base software (formally known as NOS).

Try getting that level of flexibility/performance improvements with legacy 3 tier!

Next up, Part 2

 

Peak performance vs Real World – Exchange on Nutanix Acropolis Hypervisor (AHV)

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I wrote a post in April 2015 titled “Peak Performance vs Real World Performance” which discusses how benchmarks are not realistic and the performance shown in benchmarks can rarely be reproduced with real workloads. It has been one of my most popular posts, and I have had overwhelmingly positive feedback, with only a select few still pushing unrealistic peak performance benchmarks as being of value to customers.

I thought I would whip up a post showing an example of benchmarks vs real world performance requirements using MS Exchange Jetstress on Nutanix.

The below is a screen shot from Nutanix PRISM HTML based GUI showing a Virtual Machines Read/Write IOPS , bandwidth and latency during a MS Exchange Jetstress benchmark.

JetstressAHV20160105

The screen shot shows ~4000 Read IOPS and ~4000 Write IOPS at a latency of 1.59ms.

But what does the above really tell us and what does it mean to a customer?

I’ve been quoted as saying “Benchmarks are of little value without context specific to customer requirements!” and I stand by this statement.

Let’s now look at an example of a real customers requirement:

The below is from the Exchange server role requirements calculator and it is a screen shot from the Role requirements tab which shows an estimate of the IOPS required for the Databases and Logs for a single Exchange instance.

ExchangeIOexample

It shows the required IOPS being 536 for the databases and 115 for the logs.

Note: The sizing calculator was for an environment supporting 20000 mailboxes across 3 mailbox servers. As such, the above IO requirements are for ~6666 users.

So now that we have done the MS Exchange solution sizing (shown above is just the storage performance requirements), we understand the requirement to be around 651 mixed Read/Write IOPS per mailbox VM. We can then take a benchmark such as Jetstress and validate that the solution has sufficient storage performance.

To require the ~8000 IOPS the Jetstress test showed, we would need to scale up each Exchange instances to support have a much larger number of users and have each user send/receive 500 emails per day to reach this requirement.

8kJetstressIOPS

But in scaling up each Exchange instance to reach the peak IOPS that even this 3 year old generation Nutanix node can deliver we would vastly exceed the compute sizing recommendations for Exchange 2013 (being 24vCPUs and 96GB RAM) as shown by the calculator below.

ScaleUpExchange

As we can see, for an Exchange instance to require those peak IOPS, we would have to size the Mailbox server VMs with more than 10x the recommended vCPUs (24) and 15x the RAM (96GB). This shows that peak IOPS which can be achieved are not relevant in the real world.

In fact, Exchange generally does not require more than 1000 IOPS. Typically its requires much less, as my earlier example shows. So peak performance numbers are of little/no value as they can’t (and more importantly don’t need to be) reproduced in the real world.

With a tool like Jetstress we can configure a precise Mailbox profiles and test only what you require. If the solution can produce more IOPS than what you need (such as in this example), that’s fine for headroom, but in this day and age where Nutanix allows you to quickly and easily scale (Compute/Storage performance & capacity), I recommend designing for what you need in the foreseeable future (by this I mean 6-12 months) and scale if/when required.

What a benchmark does help you understand is how much headroom a solution has over and above your requirements which can help choose a solution to support mixed workloads, BUT the benchmark would need to be re-ran concurrently with suitable benchmarks for all other applications you intend on mixing to see how the solution behaves with mixed workloads.

As such, single application peak performance benchmarks are almost never valuable (to customers) unless your planning to run application specific silos. I strongly recommend anyone considering implementing an application specific silo, read the following article: Enterprise Architecture & Avoiding tunnel vision.

And… if you’re planning to run application specific silos and/or scaling up workloads to the point they need crazy IOPS, then you’re increasing the size of your failure domains, CAPEX and OPEX which is only doing yourself (or your customer) a disservice. But that’s a topic for another day.

I hope this example shows how real world requirements and performance is vastly different to what a benchmark shows and why peak performance benchmarks should be taken with a grain of salt.

I’ve always said the focus should be on gathering requirements and delivering on business outcomes, not focusing on performance which is typically only a very small part of a solution that delivers a successful business outcome.

Summary:

When sizing an MS Exchange solution on Nutanix, IOPS is not a constraining factor even for large scale deployments. The most common constraining factor is the Microsoft recommended compute maximums being 24 vCPUs and 96GB RAM, which is the same constraint regardless of if you run on Nutanix, or any other virtual / physical platform.

Related Articles:

MS Exchange on Nutanix now a MS validated ESRP solution

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I am pleased to announce that Nutanix has successfully completed the Microsoft Exchange Solution Review Program requirements and are now listed as a validated solution at the following URL:

Exchange Solution Reviewed Program (ESRP) – Storage

The solution shows a dual site 24,000 1GB Mailbox solution running on just 8 NX-8150 nodes. This is a very highly resilient solution with N+1 availability at each site allowing for full self healing and failover in the event of a node failure.

Nutanix is also the FIRST and only hyper-converged platform to be validated under ESRP, further strengthening our leadership in the market.

The performance testing (using Jetstress) was with the nodes at around 90% capacity with 8.5TB per node, proving that Nutanix provided great performance even when running at high utilization and where the working set far exceeds the SSD tier. This is key to a truly enterprise solution for a business critical application such as Exchange.

The solution is running on Hyper-V with SMB 3.0 on the underlying Nutanix Distributed Storage Fabric. The same solution can also be deployed on vSphere or Acropolis Hypervisors using iSCSI in a fully supported configuration.

The above solution was validated without using Compression or Erasure Coding both of which improve performance and give significant capacity savings which allows for larger mailboxes. As a result, the Nutanix platform provides even more value than the ESRP submission shows.

If there was any doubt around if you should virtualize MS Exchange on Nutanix platform, the fact Nutanix is now validated by Microsoft should put your mind at ease.

Now you can move one step closer to a fully webscale datacenter by removing another application specific silo and enjoy improved resiliency/performance while reducing operational cost and complexity.