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Solving Oracle & SQL Licensing challenges with Nutanix

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The Nutanix platform has and will continue to evolve to meet/exceed the ever increasing customer and application requirements while working within constraints such as licensing.

Two of the most common workloads which I work frequently with customers to design solutions around real or perceived licensing constraints are Oracle and SQL.

In years gone by, Nutanix solutions were constrained to being built around a limited number of node types. When I joined in 2013 only one type existed (NX-3450) which limited customers flexibility and often led to paying more for licensing than a traditional 3-tier solution.

With that said, the ROI and TCO for the Nutanix solutions back then were still more often than not favourable compared to 3-tier but these days we only have more and more good news for prospective and existing customers.

Nutanix has now rounded out the portfolio with the introduction of “Compute Only” nodes to target a select few niche workloads with real or perceived licensing and/or political constraints.

Compute only nodes compliment the traditional HCI nodes (Compute+Storage) as well as our unique Storage Only Nodes which were introduced in mid 2015.

So how do Compute Only nodes help solve these licensing challenges?

In short, Oracle leads the world in misleading and intimidating customers into paying more for licensing than what they need to. One of the most ridiculous claims is “You must license every physical CPU core in your cluster because Oracle could run or have ran on it”.

The below tweet makes fun of Oracle and shows how ridiculous their claim that customers need to license every node in a cluster (which I’ve never seen referenced in any actual contract) is.

So let’s get to how you can design a Nutanix solution to meet a typical Oracle customer licensing constraint while ensuring excellent Scalability, Resiliency and Performance.

At this stage we now assume you’ve given your first born child and left leg to Oracle and have subsequently been granted for example 24 physical core licenses from Oracle, what next?

If we we’re to use HCI nodes, some of the CPU would be utilised by the Nutanix Controller VM (CVM) and while the CVM does add a lot of value (see my post Cost vs Reward for the Nutanix Controller VM) you may be so constrained by licensing that you want to maximise the CPU power for just Oracle workloads.

Now in this example, we have 24 licensed physical cores, so we could use two Compute Only nodes using an Intel Gold 6128 [6 cores / 3.4 GHz] / 12 cores per server for 24 total physical cores.

Next we would assess the storage capacity, resiliency and performance requirements and decide how many and what configuration storage only nodes are required.

Because Virtual Machines cannot run on storage only nodes, the Oracle Virtual Machines cannot and will never run on any other CPU cores other than the two Compute Only nodes therefore you would be in compliance with your licensing.

The below is an example of what the environment could look like.

2CO_4SOnodes

SQL has ever changing CPU licensing models which in some cases are licensed by server or vCPU count, Compute Only can be used in the same way I explained above to address any SQL licensing constraints.

What about if I need to scale storage capacity and/or performance?

You’re in luck, without any modifications to the Oracle workloads, you can simply add one or more storage only nodes to the cluster and it will almost immediately increase capacity, performance and resiliency!

I’ve published an example of the performance improvement by adding storage only nodes to a cluster in an article titled Scale out performance testing with Nutanix Storage Only Nodes which I wrote back in 2016.

In short, the results show by doubling the number of nodes from 4 to 8, the performance almost exactly doubled while delivering low read and write latency.

What if you’ve already invested in Nutanix HCI nodes (example below) and are running Oracle/SQL or any other workloads on the cluster?

TypicalHCIcluster

Nutanix provides the ability to convert a HCI node into a Storage Only node which results in preventing Virtual Machines from running on that node. So all you need to do is add two or more Compute Only nodes to the cluster, then mark the existing HCI nodes as Storage Only and the result is shown below.

CO_PlusConvertedHCI

This is in fact the minimum supported configuration for Compute Only Environments to ensure minimum levels of resiliency and performance. For more information, check out my post “Nutanix Compute Only Minimum requirements“.

Now we have two nodes (Compute Only) which can run Virtual Machines and four nodes (HCI nodes converted to Storage Only) which are servicing the storage I/O. In this scenario, if the HCI nodes have unused CPU and/or RAM the Nutanix Controller VM (CVM) can also be scaled up to drive higher performance & lower latency.

Compute Only is currently available with the Nutanix Next Generation Hypervisor “AHV”.

Now let’s cover off a few of the benefits of running applications like Oracle & SQL on Nutanix:

  1. No additional Virtualization licensing (AHV is included when purchasing Nutanix AOS)
  2. No rip and replace for existing HCI investment
  3. Unique scale out distributed storage fabric (ADSF) which can be easily scaled as required
  4. Storage Only nodes add capacity, performance and resiliency to your mission critical workloads without incurring additional hypervisor or application licensing costs
  5. Compute Only allows scale up and out of CPU/RAM resources where applications are constrained by ONLY CPU/RAM and/or application software licensing.
  6. Storage Only nodes can also provide functions such as Nutanix Files (previously known as Acropolis File Services or AFS)

As a result of Nutanix now having HCI, Storage Only and Compute Only nodes, we’re now entering the time where Nutanix can truely be the standard platform for almost any workload including those with non technical constraints such as political or application licensing which have traditionally been at least perceived to be an advantage for legacy SAN products.

The beauty of the Nutanix examples above is while they look like a traditional 3-tier, we avoid the legacy SAN problems including:

1. Rip and Replace / High Impact / High Risk Controller upgrades/scalability
2. Difficulty in scaling performance with capacity
3. Inability to increase resiliency without adding additional Silos of storage (i.e.: Another dual controller SAN)

With Compute Only being supported by AHV, we also help customers avoid the unnecessary complexity and related operational costs of managing ESXi deployments which have become increasingly more complex over time without significantly improving value to the average customer who simply wants high performance, resilient and easy to manage virtualisation solution.

But what about VMware ESXi customers?

Obviously moving to AHV would be ideal but for those who cannot for whatever reasons can still benefit from Storage Only nodes which provide increased storage performance and resiliency to the Virtual machines running on ESXi.

Customers can run ESXi on Nutanix (or OEM / Software Only) HCI nodes and then scale the clusters performance/capacity with AHV based storage only nodes, therefore eliminating the need to license both ESXi and Oracle/SQL since no virtual machine will run on these nodes.

How does Nutanix compare to a leading all flash array?

For those of you who would like to see a HCI only Nutanix solution have better TCO as well as performance and capacity than a leading All Flash Array, checkout A TCO Analysis of Pure FlashStack & Nutanix Enterprise Cloud where even with giving every possible advantage to Pure Storage, Nutanix still comes out on top without data reduction assumptions.

Now consider that Nutanix the TCO as well as performance and capacity was better than a leading All Flash Array with only HCI nodes, imagine the increased efficiency and flexibility by being able to mix/match HCI, with Storage Only and Compute only.

This is just another example of how Nutanix is eliminating even the corner use cases for traditional SAN/NAS.

For more information about Nutanix Scalability, Resiliency and Performance, checkout this multi-part blog series.

Nutanix Scalability – Part 5 – Scaling Storage Performance for Physical Machines

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Part 3 and Part 4 has taught us that Nutanix provides excellent scalability for Virtual Machines and provides ABS and Volume Group Load Balancer (VG LB) for niche workloads which may require more performance than a single node can provide.

Now that we’ve learned how to scale a Virtual machines performance, let’s see how the same rules apply to physical servers.

So you’ve got your physical server and a Nutanix cluster, now what?

As Part 3 and Part 4 explained, more virtual disks increase the storage performance for virtual machine, the same is true for physical servers using ABS.

Virtual disks will be presented to the physical server via iSCSI (ABS), for optimal performance you should have at least one virtual disk per node in your cluster. The reason for this is each vDisk is managed by a stargate (Nutanix IO engine) instance which runs in every Controller VM (CVM).

If you have a four node cluster, you need to use at least four virtual disks to utilise the four node cluster optimally. For an eight node cluster, eight or more virtual disks is required to ensure all CVMs (stargate instances) can actively provide a boost in performance.

The following tweet shows how the pathing increased from four on the four node cluster and when an additional fours node were added the pathing dynamically changed to use all eight nodes.

Therefore when using ABS for physical workloads, especially those high end database servers, I recommend using a minimum of 8 vDisks however if your cluster size is greater than 8, match the number of vDisks with the cluster size as your starting point.

If you have an 8 node cluster, you could for example use 32 vDisks and these will spread evenly across the nodes, resulting in four per stargate instance which is perfectly fine.

Using more vDisks than your current cluster size also means when additional nodes are added, ABS can dynamically load balance the vDisks across the new and existing nodes to automatically scale your performance.

Let’s cover the same MS Exchange and MS SQL examples covered for Virtual Machines in Parts 3 and 4 but now specifically for physical servers using ABS.

Let’s say we have an MS Exchange server with 20 databases, the performance requirements for each database is typically in the range of hundred of IOPS, in which case I would recommend one virtual disk (e.g.: VMDK) per database and another for the logs.

In the case of a large MS SQL server which may require tens or hundreds of thousands of IOPS to a single database, I recommend using multiple vDisks per database which involves Splitting SQL datafiles across multiple VMDKs to optimise VM physical server performance.

Sound familiar? The above two paragraphs are literally a copy/paste from Part 3 because the exact same rules apply to physical servers and virtual machines. Simple right!

Still need more performance?

Again, the exact same rules apply to physical servers with ABS as they do to virtual machines. In no particular order, as we’ve learned from Part 3 & 4:

  • Increase the vCPU of the Nutanix Controller VM (CVM)
  • Increase the vRAM of the Nutanix Controller VM (CVM)
  • Add storage only nodes

Can’t get much easier than that!

Summary:

From Parts 3, 4 and 5 we have learned that Nutanix provides the ability to scale the performance of individual servers, be it physical or virtual using the same simple strategies of adding virtual disks, storage only nodes or Controller VM (CVM) resources and how doing so increases performance to meet virtually (pun intended) any performance requirements.

Is there any reason you couldn’t confidently say Nutanix is doing 3 tier better than the SAN vendors? I’d love to hear if you have any corner cases.

Back to the Scalability, Resiliency and Performance Index.

Nutanix Scalability – Part 4 – Storage Performance for Monster VMs with AHV!

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In Part 3 we learned a number of ways to scale storage performance for a single VM including but not limited too:

  • Using multiple PVSCSI controllers
  • Using multiple virtual disks
  • Spreading large workloads (like databases) across multiple vDisks/Controllers
  • Increasing the CVMs vCPUs and/or vRAM
  • Adding storage only nodes
  • Using Acropolis Block Services (ABS)

Now here at Nutanix, especially in the Solutions/Performance engineering team we’re never satisfied and we’re always pushing for more efficiency which leads to greater performance.

A colleague of mine, Michael Webster (NPX#007 and VCDX#66) was a key part of the team who designed and developed what is now known as “Volume Group Load Balancer” or VG LB for short.

Volume Group Load Balancer is an Acropolis Hypervisor (AHV) only capability which combines the IO path efficiencies of AHV Turbo Mode with the benefits of the Acropolis Distributed Storage Fabric (ADSF) to create a more simplified and dynamic version of Acropolis Block Services (ABS).

One major advantage of VG LB over ABS is it’s simplicity.

There is no requirement for in-guest iSCSI which removes the potential for driver and configuration issues and VG LB is configured through PRISM UI by using the update VM option making it a breeze to setup.

UpdateVMwVG

The only complexity with VG LB currently is to enable the load balancing functionality, it needs to be applied at the Acropolis CLI (acli) using the following command:

acli vg.update Insert_vg_name_here load_balance_vm_attachments=true

In the event you do not wish all Controller VMs to provide IO for VG LB, one or more CVMs can be excluded from load balancing. However I recommend leaving the cluster to sort itself out as the Acropolis Dynamic Scheduler (ADS) will move virtual disk sessions if CVM contention is discovered.

iSCSI sessions are also dynamically balanced as workload on individual CVMs exceed 85% to ensure hot spots are quickly alleviated which is another reason why CVMs should not be excluded as you are likely constraining performance for the VG LB VM unnecessarily.

VG LB is how Nutanix has achieved >1 MILLION 8k random read IOPS at just 0.11ms latency from a single VM as shown below.

This was achieved using just a 10 node cluster, imagine what can be achieved when you scale out the cluster further.

A Frequently asked question relating to high performance VMs is what happens when you vMotion?

The link above shows this in detail including a YouTube demonstration, but in short the IO dropped below 1 million IOPS for approx 3 seconds during the vMotion with the lowest value recorded at 956k IOPS. I’d say an approx 10% drop for 3 seconds is pretty reasonable as the performance drop is caused by the migration stunning the VM and not by the underlying storage.

The next question is “What about mixed read/write workloads?”

Again the link above shows this in detail including a YouTube demonstration, but at this stage you’re probably not surprised that this result shows a maximum starting baseline of 436K random read and 187k random write IOPS and immediately following the migration performance reduced to 359k read and 164k write IOPS before achieving greater performance than the original baseline @ 446k read and 192k IOPS within a few seconds.

So not only can Nutanix VG LB achieve fantastic performance, it can do so during normal day to day operations such as VM live migrations.

The VG LB capability is unique to Nutanix and is only achievable thanks to the true Distributed Storage Fabric.

With Nutanix highly scalable software defined storage and the unique capabilities like storage only nodes, AHV Turbo and VG LB, the question “Why?” seriously needs to be asked of anyone recommending a SAN.

I’d appreciate any constructive questions/comments on use cases which you believe Nutanix cannot handle and I’ll follow up with a blog post explaining how it can be done, or I’ll confirm if it’s not currently supported/recommended.

Summary:

Part 3 has taught us that Nutanix provides excellent scalability for Virtual Machines and provides ABS for niche workloads which may require more performance than a single node can offer while Part 4 explains how Nutanix’ next generation hypervisor (AHV) provides further enhanced and simplified performance for monster VMs with Volume Group Load Balancing leveraging Turbo Mode.

Back to the Scalability, Resiliency and Performance Index.