Exploring the customer experience with lifecycle management for vSAN Ready Nodes and VxRail clusters
Thu, 24 Sep 2020 19:41:49 -0000|
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The difference between VMware vSphere LCM (vLCM) and Dell EMC VxRail LCM is still a trending topic that most HCI customers and prospects want more information about. While we compared the two methods at a high level in our previous blog post, let’s dive into the more technical aspects of the LCM operations of VMware vLCM and VxRail LCM. The detailed explanation in this blog post should give you a more complete understanding of your role as an administrator for cluster lifecycle management with vLCM versus VxRail LCM.
Even though vLCM has introduced a vast improvement in automating cluster updates, lifecycle management is more than executing cluster updates. With vLCM, lifecycle management is still very much a customer-driven endeavor. By contrast, VxRail’s overarching goal for LCM is operational simplicity, by leveraging Continuously Validated States to drive cluster LCM for the customer. This is a large part of why VxRail has over 8,600 customers since it was launched in early 2016.
In this blog post, I’ll explain the four major areas of LCM:
- Defining the initial baseline configuration
- Planning for a cluster update
- Executing the cluster update
- Sustaining cluster integrity over the long term
Defining the initial baseline configuration
The baseline configuration is a vital part of establishing a steady state for the life of your cluster. The baseline configuration is the current known good state of your HCI stack. In this configuration, all the component software and firmware versions are compatible with one another. Interoperability testing has validated full stack integrity for application performance and availability while also meeting security standards in place. This is the ‘happy’ state for you and your cluster. Any changes to the configuration use this baseline to know what needs to be rectified to return to the ‘happy’ state.
How is it done with vLCM?
vLCM depends on the hardware vendor to provide a Hardware Management Services virtual machine. Dell provides this support for its Dell EMC PowerEdge servers, including vSAN ReadyNodes. I’ll use this implementation to explain the overall process. Dell EMC vSAN ReadyNodes use the OpenManage Integration for VMware vCenter (OMIVV) plugin to connect to and register with the vCenter Server.
Once the VM is deployed and registered, you need to create a credential-based profile. This profile captures two accounts: one for the out-of-band hardware interface, the iDRAC, and the other for the root credentials for the ESXi host. Future changes to the passwords require updating the profile accordingly.
With the VM connection and profile in place, a Catalog XML file is used by vLCM to define the initial baseline configuration. To create the Catalog XML file, you need to install and configure the Dell Repository Manager (DRM) to build the hardware profile. Once a profile is defined to your specification, it must then be exported and stored on an NFS or CIFS share. The profile is then used to populate the Repository Profile data in the OMIVVV UI. If you are unsure of your configuration, refer to the vSAN Hardware Compatibility List (HCL) for the specific supported firmware versions. Once the hardware profile is created, you can then associate it with the cluster profile. With the cluster profile defined, you can enable drift detection. Any future change to the Catalog XML file is done within the DRM.
It’s important to note that vLCM was introduced in vSphere 7.0. To use vLCM, you must first update or deploy your clusters to run vSphere 7.x.
How is it done with VxRail LCM?
With VxRail, when the cluster arrives at the customer data center, it’s already running in a ‘happy’ state. For VxRail, the ‘happy’ state is called Continuously Validated States. The term is pluralized because VxRail defines all the ‘happy’ states that your cluster will update to over time. This means that your cluster is always running in a ‘happy’ state without you needing to research, define, and test to arrive at Continuously Validated States throughout the life of your cluster. VxRail – well, specifically the VxRail engineering team - does it for you. This has been a central tenet of VxRail since the product first launched with vSphere 6.0. Since then it has helped customers transition to vSphere 6.5, 6.7, and now 7.0.
Once the VxRail cluster initialization is completed, use your Dell EMC Support credentials to configure the VxRail repository setting within vCenter. VxRail Manager plugin to vCenter will automatically connect to the VxRail repository at Dell EMC and pull down the next available update package.
Figure 1 Defining the initial baseline configuration
Planning for a cluster update
Updates are a constant in IT, and VMware is constantly adding new capabilities or product/security fixes that require updating to newer versions of software. Take for example the vSphere 7.0 Update 1 release that VMware and Dell Technologies just announced. Those eye-opening features are available to you when you update to that release. You can check out just how often VMware has historically updated vSphere here: https://kb.vmware.com/s/article/2143832.
As you know, planning for a cluster update is an iterative process with inherent risk associated with it. Failing to plan diligently can cause adverse effects on your cluster, ranging from network outages and node failure to data unavailability or data loss. That said, it’s important to mitigate the risk where you can.
How is it done with vLCM?
With vLCM, the responsibility of planning for a cluster update rests on the customers’ shoulders, including the risk. Understanding the Bill of Materials that makes up your server’s hardware profile is paramount to success. Once all the components are known, and a target version of vSphere ESXi is specified, the supported driver and firmware version needs to be investigated and documented. You must consult the VMware Compatibility Guide to find out which drivers/firmware are supported for each ESXi release.
It is important to note that although vLCM gives you the toolset to apply firmware and driver updates, it does not validate compatibility or support for each combination for you, except for the HBA Driver. This task is firmly in the customer’s domain. It is advisable to validate and test the combination in a separate test environment to ensure that no performance regression or issues are introduced into the production environment. Interoperability testing can be an extensive and expensive undertaking. Customers should create and define robust testing processes to ensure that full interoperability and compatibility is met for all components managed and upgraded by vLCM.
With Dell EMC vSAN Ready Nodes, customers can rest assured that the HCL certification and compatibility validation steps have been performed. However, the customer is still responsible for interoperability testing.
How is it done with VxRail LCM?
VxRail engineering has taken a unique approach to LCM. Rather than leaving the time-consuming LCM planning to already overburdened IT departments, they have drastically reduced the risk by investing over $60 million, more than 25,000 hours of testing for major releases, and more than 100 team members into a comprehensive regression test plan. This plan is completed prior to every VxRail code release. (This is in addition to the testing and validation performed by PowerEdge, on which VxRail nodes are built.)
Dell EMC VxRail engineering performs this testing within 30 days of any new VMware release (even quicker for express patches), so that customers can continually benefit from the latest VMware software innovations and confidently address security vulnerabilities. You may have heard this called “synchronous release”.
The outcome of this effort is a single update bundle that is used to update the entire HCI stack, including the operating system, the hardware’s drivers and firmware, and management components such as VxRail Manager and vCenter. This allows VxRail to define the declarative configuration we mentioned previously (“Continuously Validated States”), allowing us to move easily from one validated state to the next with each update.
Figure 2 Planning for a cluster update
Executing the cluster update
The biggest improvement with vLCM is its ability to orchestrate and automate a full stack HCI cluster update. This simplifies the update operation and brings enormous time savings. This process is showcased in a recent study performed by Principled Technologies with PowerEdge Servers with vSphere (not including vSAN).
How is it done with vLCM?
The first step is to import the ESXi ISO via the vLCM tab in the vCenter Server UI. Once uploaded, select the relevant cluster, ensure that the cluster profile (created in the initial baseline configuration phase) is associated with the cluster being updated. Now, you can apply the target configuration by editing the ESXi image and, from the OMIVV UI, choose the correct firmware and driver to apply to the hardware profile. Once a compliance scan is complete, you will have the option to remediate all hosts.
If there are multiple homogenous clusters you need to update, it can be as easy as using the same cluster profile to execute the cluster update against. However, if the next cluster has a different hardware configuration, then you would have to perform the above steps over again. Customers with varying hardware and software requirements for their clusters will have to repeat many of these steps, including the planning tasks, to ensure stack integrity.
How it is done with VxRail LCM?
With VxRail and Continuously Validated States, updating from one configuration to another is even simpler. You can access the VxRail Manager directly within the vCenter Server UI to initiate the update. The LCM operation automatically retrieves the update bundle from the VxRail repository, runs a full stack pre-update health check, and performs the cluster update.
With VxRail, performing multi-cluster updates is as simple as performing a single-cluster update. The same LCM cluster update workflow is followed. While different hardware configurations on separate clusters will add more labor for IT staff for vSAN Ready Nodes, this doesn’t apply to VxRail. In fact, in the latest release of our SaaS multi-cluster management capability set, customers can now easily perform cluster updates at scale from our cloud-based management platform, MyVxRail.
Figure 3 Executing a cluster update
Sustaining cluster integrity over the long term
The long-term integrity of a cluster outlasts the software and hardware in it. As mentioned earlier, because new releases are made available frequently, software has a very short life span. While hardware has more staying power, it won’t outlast some of the applications running on them. New hardware platforms will emerge. New hardware devices will enter the market that will launch new workloads, such as machine learning, graphics rendering, and visualization workflows. You will need the cluster to evolve non-disruptively to deliver the application performance, availability, and diversity your end-users require.
How is it done with vLCM?
In its current form, vLCM will struggle in long-term cluster lifecycle management. In particular, its inability to support heterogeneous nodes (nodes with different hardware configurations) in the same cluster will limit its application diversification and its ability to take advantage of new hardware platforms without impacting end-users.
How it is done with VxRail LCM?
VxRail LCM touts its ability to allow customers to grow non-disruptively and to scale their clusters over time. That includes adding non-identical nodes into the clusters for new applications, adding new hardware devices for new applications or more capacity, or retiring old hardware from the cluster.
Figure 4 Comparing vSphere LCM and VxRail LCM cluster update operations driven by the customer
The VMware vLCM approach empowers customers who are looking for more configuration flexibility and control. They have the option to select their own hardware components and firmware to build the cluster profile. With this freedom comes the responsibility to define the HCI stack and make investments in equipment and personnel to ensure stack integrity. vLCM supports this customer-driven approach with improvements in cluster update execution for faster outcomes.
Dell EMC VxRail LCM continues to take a more comprehensive approach to optimize operational efficiency from the point of the view of the customer. VxRail customers value its LCM capabilities because it reduces operational time and effort which can be diverted into other areas of need in IT. VxRail takes on the responsibility to drive stack integrity for the lifecycle management of the cluster with Continuously Validated States. And VxRail sustains stack integrity throughout the life of the cluster, allowing you to simply and predictably evolve with technology trends.
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I feel the need – the need for speed (and endurance): Intel Optane edition
Tue, 12 Oct 2021 21:38:31 -0000|
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It has only been three short months since we launched VxRail on 15th Generation PowerEdge, but we're already expanding the selection of configuration offerings. So far we've added 18 additional processors to power your workloads, including some high frequency and low core count options. This is delightful news for those with applications that are licensed per core, an additional NVIDIA GPU - the A30, a slew of additional drives, and doubled the RAM capacity to 8TB. I've probably missed something, as it can be hard to keep up with the all the innovations taking place within this race car that is VxRail!
In my last blog, I hinted at one of those drive additions, faster cache drives. Today I'm excited to announce that you can now order, and turbo charge your VxRail with the 400GB or 800GB Intel P5800X – Intel’s second generation Optane NVMe drive. Before we delve into some of the performance numbers, let’s discuss what it is about the Optane drives that makes them so special. More specifically, what is it about them that enables them to deliver so much more performance, in addition to significantly higher endurance rates.
To grossly over-simplify it, and my apologies in advance to the Intel engineers who poured their lives into this, when writing to NAND flash an erase cycle needs to be performed before a write can be made. These erase cycles are time-consuming operations and the main reason why random write IO capabilities on NAND flash is often a fraction of the read capability. Additionally, a garbage collection is running continuously in the background to ensure that there is space available to incoming writes. Optane, on the other hand, does bit-level write in place operations, therefore it doesn’t require an erase cycle, garbage collection, or performance penalty writes. Hence, random write IO capability almost matches the random read IO capability. So just how much better is endurance with this new Optane drive? Endurance can be measured in Drive Writes Per Day (DWPD), which measures how many times the drive's entire size could be overwritten each day of its warranty life. For the 1.6TB NVMe P5600 this is 3 DWPD, or 55 MB per second, every second for five years – just shy of 9PB of writes, not bad. However, the 800GB Optane P5800X will endure 146PB over its five-year warranty life, or almost 1 GB per second (926 MB/s) every second for its five year 100 DWPD warranty life. Not quite indestructible, but that is a lot of writes, so much so you don’t need extra capacity for wear leveling and a smaller capacity drive will suffice.
You might wonder why you should care about endurance, as Dell EMC will replace the drive under warranty anyway – there are three reasons. When a cache drive fails, its diskgroup is taken offline, so not only have you lost performance and capacity, your environment is taking on the additional burden of a rebuild operation to re-protect your data. Secondly, more and more systems are being deployed outside of the core data center. Replacing a drive in your data center is straightforward, and you might even have spares onsite, but what about outside of your core datacenter? What is your plan for replacing a drive at a remote office, or a thousand miles away? What if that remote location is not an office but an oilrig one hundred miles offshore, or a cruise ship halfway around the world where the cost of getting a replacement drive there is not trivial? In these remote locations, onsite spares are commonplace, but the exceptions are what lead me to the third reason, Murphy's Law. IT and IT staffing might be an afterthought at these remote locations. Getting a failed drive swapped out at a remote location which lacks true IT staffing may not get the priority it deserves, and then there is that ever present risk of user error... “Oh, you meant the other drive?!? Sorry...”
Cache in its many forms plays an important role in the datacenter. Cache enables switches and storage to deliver higher levels of performance. On VxRail, our cache drives fall into two categories, SAS and NVMe, with NVMe delivering up to 35% higher IOPS and 14% lower latency. Among our NVMe cache drive we have two from Intel, the 1.6TB P5600 and the Optane P5800X, in 400GB and 800GB capacities. The links for each will bring you to the drive specification including performance details. But how does the performance at a drive level impact performance at the solution level? Because, at the end of the day that is what your application consumes at the solution level, after cache mirroring, network hops, and the vSAN stack. Intel is a great partner to work with, when we checked with them about publishing solution level performance data comparing the two drives side-by-side, they were all for it.
In my over-simplified explanation above, I described how the write cycle for Optane drives is significantly different as an erase operation and does not need to be done first. So how does that play out in a full solution stack? Figure 1 compares a four node VxRail P670F cluster, running a 100% sequential write 64KB workload. Not a test that reflects any real-world workload, but one that really stresses the vSAN cache layer, highlights the consistent write performance that 3D XPoint technology delivers, and shows how Optane is able to de-stage cache when it fills up without compromising performance.
Figure 1: Optane cache drives deliver consistent and predictable write performance
When we look at performance, there are two numbers to keep in mind: IOPS and latency. The target is to have high IOPS with low and predictable latency, at a real-world IO size and read:write ratio. To that end, let’s look at how VxRail performance differs with the P5600 and P5800X under OLTP32K (70R30W) and RDBMS (60R40W) benchmark workload, as shown in Figure 2.
Figure 2: Optane cache drives deliver higher performance and lower latency across a variety of workload types.
It doesn't take an expert to see that with the P5800X this four node VxRail P670F cluster's peak performance is significantly higher than when it is equipped with the P5600 as a cache drive. For RDBMS workloads up to 44% higher IOPS with a 37% reduction in latency. But peak performance isn't everything. Many workloads, particularly databases, place a higher importance on latency requirements. What if our workload, database or otherwise, requires 1ms response times? Maybe this is the Service Level Agreement (SLA) that the infrastructure team has with the application team. In such a situation, based on the data shown, and for a OLTP 70:30 workload with a 32K block size, the VxRail cluster would deliver over twice the performance at the same latency SLA, going from 147,746 to 314,300 IOPS.
In the datacenter, as in life, we are often faced with "Good, fast, or cheap. Choose two." When you compare the price tag of the P5600 and P5800X side by side, the Optane drive has a significant premium for its good and fast. However, keep in mind that you are not buying an individual drive, you are buying a full stack solution of several pieces of hardware and software, where the cost of the premium pales in comparison to the increased endurance and performance. Whether you are looking to turbo charge your VxRail like a racecar, or make it as robust as a tank, Intel Optane SSD drives will get you both.
David Glynn, Technical Marketing Engineer, VxRail at Dell Technologies
LinkedIn: David Glynn