Enabling high performance for HCI workloads is exactly what happens when VxRail is configured with Intel Optane Persistent Memory (PMem). Optane PMem provides compute and storage performance to better serve applications and business-critical workloads. So, what is Intel Optane Persistent Memory? Persistent memory is memory that can be used as storage, providing RAM-like performance, very low latency and high bandwidth. It’s great for applications that require or consume large amounts of memory like SAP HANA, and has many other use cases as shown in Figure 1 and VxRail is certified for SAP HANA as well as Intel Optane PMem.  

Moreover, PMem can be used as block storage where data can be written persistently, a great example is for DBMS log files. A key advantage to using this technology is that you can start small with a single PMem card (or module), then scale and grow as needed with the ability to add up to 12 cards. Customers can take advantage of PMem immediately because there’s no need to make major hardware or configuration changes, nor budget for a large capital expenditure. 

There are a wide variety of use cases today including those you see here:

Figure 1: Intel Optane PMem Use Cases

PMem offers two very different operating modes, that being Memory and App Direct, and in turn App Direct can be used in two very different ways.

First, Intel Optane PMem in Memory mode is not yet supported by VxRail.  This mode acts as volatile system memory and provides significantly lower cost per GB then traditional DRAM DIMMs. A follow-on update to this blog will describe this mode and test results in much more detail once it is supported.

As for App Direct mode (supported today), PMem is consumed by virtual machines as either a block storage device, known as vPMemDisk, or as byte addressable memory, known as Virtual NVDIMM. Both provide great benefit to the applications running in a virtual machine, just in very different ways. vPMemDisk can be used by any virtual machine hardware, and by any Guest OS.  Since it’s presented as a block device it will be treated like any other virtual disk. Applications and/or data can then be placed on this virtual disk. The second consumption method, NVDIMM has the advantage of being addressed in the same way as regular RAM, however, it can retain its data through reboots or power failures. This is a considerable plus for large in-memory databases like SAP HANA where cache warm-up or the time to load tables in memory  can be significant!

However, it’s important to note that, like any other memory module, the PMem module does not provide data redundancy. This may not be an issue for some data files on commonly used applications that can be re-created in case of a host failure. But a key principle when using PMem, either as block storage or byte addressable memory is that the applications are responsible for handling data replication to provide durability. 

New data redundancy options are expected on applications that are using PMem and should be well understood before deployment.

First, we’ll look at test results using PMem as virtual disk (or vPMemDisk). Our Engineering team tested VxRail with PMem in App Direct mode and ran comparison tests against a VxRail all-flash (P570F series platform). The testing simulated a typical 4K OLTP workload with 70/30 RW ratio. Our results achieve more than 1.8M IOPs or 6X more than the all-flash VxRail system. That equates to 93% faster response times (or lower latency) and 6X greater throughput as shown here:

Figure 2: VxRail PMem App Direct versus VxRail all-flash

This latency difference indicates the potential to improve the performance of legacy applications by placing specific data files on a PMem module, for example, placing log files on PMem. To verify the benefit of this log acceleration use case we ran a TPC-C benchmark comparing VxRail configured with a log file on a vPMEMDIsk to a VxRail all-flash vSAN, and we saw a 46% improvement on the number of transactions per minute.

Figure 3: Log file acceleration use case

For the second consumption method, we tested PMem in App direct mode using the NVDIMM consumption method. We performed tests using 1,2,4,8 and then 12 PMEM modules. All testing has been evaluated and validated by ESG (Enterprise Strategy Group). The certified white paper has been published as highlighted in the resources section.

Figure 4: NVDIMM device testing (vSAN not-optimized versus optimized PMem NVDIMM)

The results prove linear scalability as we increase the number of modules from 1 to 12. And with 12 PMem modules, VxRail achieves 80 times more IOPs than when running against vSAN not optimized (meaning VxRail all-flash vSAN with no PMem involved), and 100X for the 4K RW workload. The right half of the graphic depicts throughput results for very large IO, 64KB. When PMem is optimized on 12 modules we saw 28X higher throughput for a 64KB random read (RR) workload, and PMem is 13 times faster for the 64K RW.

What you see here is amazing performance on a single VxRail host and almost linear scalability when adding PMem!! Yes, that warrants a double bang. If you were to max out a 64-node cluster, the potential scalability is phenomenal and game changing! 

So, what does all this mean? Key takeaways are:  

• The local performance of VxRail with Intel Optane PMem can scale to 12M read IOPS, and more than 4M write IOPs or 70GB/s read throughput / 22GB/s write throughput on a single host.
• The use of PMEM modules doesn’t affect the regular activity on vSAN Datastores and extends the value of your VxRail platform in many ways;
  • It can be used to accelerate legacy applications, such as RDBMS Log acceleration
  • It enables the deployment of in memory databases and applications that can benefit from the higher IO throughput provided by PMEM while still taking the benefit of vSAN characteristics in the VxRail platform 
  • The local performance of a single host with 12 x 128GB PMem modules achieves more than 12M read IOPS, and more than 4M write IOPs
  • It not only increases performance of traditional HCI workloads such as VDI, but also support performance-intensive transactional and analytics workloads
  • It offers orders-of-magnitude faster performance than traditional storage
  • It provides more memory for less cost as PMem is much less costly than DRAM

The references and validation testing have been completed by ESG (Enterprise Strategy Group).  White papers and other resources on VxRail for Extreme Performance are available via the links listed below.

Additional Resources

ESG Validation: Dell EMC VxRail and Intel Optane Persistent Memory

VxRail and Intel Optane for Extreme Performance – Engineering presentation

High Performance for HCI Workloads with Dell EMC VxRail & Intel Optane Persistent Memory - infographic

Dell EMC & Intel Optane Persistent Memory - video

ESG Validation: Dell EMC VxRail with Intel Xeon Scalable Processors and Intel Optane SSDs

By: KJ Bedard – VxRail Technical Marketing Engineer

LinkedIn: https://www.linkedin.com/in/kj-bedard-50b25315/

Twitter: @KJbedard

The signs of autumn are all around us, from the total takeover of pumpkin-spiced everything to the beautiful fall foliage worthy of Bob Ross’s inspiration. Like the amount of change autumn brings forth, so too does the latest release of VxRail ACE, or should I preface that with ‘formerly known as’? I’ll get to that explanation shortly.

This release introduces multi-cluster update functionality that will further streamline the lifecycle management (LCM) of your VxRail clusters at scale. With this active management feature comes a new licensing structure and role-based access control to enable the active management of your clusters.

Formerly known as VxRail ACE

The colors of the leaves are changing and so is the VxRail ACE name. The brand name VxRail ACE (Analytical Consulting Engine), will no longer be used as of this release. While it had a catchy name and was easy to say, there are two reasons for this change. First, Analytical Consulting Engine no longer describes the full value or how we intend to expand the features in the future. It has grown beyond the analytics and monitoring capabilities of what was originally introduced in VxRail ACE a year ago and now includes several valuable LCM operations that greatly expand its scope. Secondly, VxRail ACE has always been part of the VxRail HCI System Software offering. Describing the functionality as part of the overall value of VxRail HCI System Software, instead of having its own name, simplifies the message of VxRail’s value differentiation.

Going forward, the capability set (that is, analytics, monitoring, and LCM operations) will be referred to as SaaS multi-cluster management -- a more accurate description. The web portal is now referred to as MyVxRail.  

Cluster updates

Cluster updates is the first active management feature offered by SaaS multi-cluster management. It builds on the existing LCM operational tools for planning cluster updates: on-demand pre-update health checks (LCM pre-check) and update bundle downloads and staging. Now you can initiate updates of your VxRail clusters at scale from MyVxRail. The benefits of cluster updates on MyVxRail tie closely with existing LCM operations. During the planning phase, you can run LCM pre-checks of the clusters you want to update. This informs you if a cluster is ready for an update and pinpoints areas for remediation for clusters that are not ready. From there, you can schedule your maintenance window to perform a cluster update and, from MyVxRail, initiate the download and staging of the VxRail update bundle onto those clusters. With this release, you can now execute cluster updates for those clusters. Now that’s operational efficiency!

When setting a cluster update operation, you have the benefit of two pieces of information – a time estimate for the update and the change data. The update time estimate will help you determine the length of the maintenance window. The estimate is generated by telemetry gathered about the install base to provide more accurate information. The change data is the list of the components that require an update to reach the target VxRail version.

Figure 1  MyVxRail Updates tab

Role-based access control

Active management requires role-based access control so that you can provide permissions to the appropriate individuals to perform configuration changes to your VxRail clusters. You don’t want anyone with access to MyVxRail to perform cluster updates on the clusters. SaaS multi-cluster management leverages vCenter Access Control for role-based access. From MyVxRail, you will be able to register MyVxRail with the vCenter Servers that are managing your VxRail clusters. The registration process will give VxRail privileges to vCenter Server to build roles with specific SaaS multi-cluster management capabilities.

MyVxRail registers the following privileges on vCenter:

• Download software bundle: downloads and stages the VxRail software bundle onto the cluster
• Execute health check: performs an on-demand pre-update health check on the cluster
• Execute cluster update: initiates the cluster update operation on the clusters
• Manage update credentials: modifies the VxRail infrastructure credentials used for active management

Figure 2  VxRail privileges for vCenter access control

VxRail Infrastructure Credentials

We’ve done more to make it easier to perform cluster updates at scale. Typically, when you’re performing a single cluster update, you have to enter the root account credentials for vCenter Server, Platform Services Controller, and VxRail Manager. That’s the same process when performing it from VxRail Manager. But that process can get tedious when you have multiple clusters to update.

VxRail Infrastructure Credentials can store those credentials so you can enter them once, at the initial setup of active management, and not have to do it again as you perform a multi-cluster update. MyVxRail can read the stored credentials that are saved on each individual cluster for security.

Big time saver! But how secure is it? More secure than hiding Halloween candy from children. For a user to perform cluster update, the administrator needs to add the ‘execute cluster update’ privilege to the role assigned to that user. Root credentials can only be managed by users assigned with a role that has the ‘manage update credentials’ privilege.

Figure 3  MyVxRail credentials manager

Licensing

The last topic is licensing. While all the capabilities you have been using on MyVxRail come with the purchase of the VxRail HCI System Software license, multi-cluster update is different. This feature requires a fee-based add-on software license called ‘SaaS active multi-cluster management for VxRail HCI System Software’. All VxRail nodes come with VxRail HCI System Software and you have access to MyVxRail and SaaS multi-cluster management features, except for cluster update. For you to perform an update of a cluster on MyVxRail, all nodes in the clusters must have the add-on software license.   

Conclusion

That is a lot to consume for one release. Hopefully, unlike your Thanksgiving meal, you can stay awake for the ending. While the brand name VxRail ACE is no more, we’re continuing to deliver value-adding capabilities. Multi-cluster update is a great feature to further your use of MyVxRail for LCM of your VxRail clusters. With role-based access and VxRail infrastructure credentials, rest assured you’re benefitting from multi-cluster update without sacrificing security.

To learn more about these features, check out the VxRail techbook and the interactive demo for SaaS multi-cluster management.

Daniel Chiu, VxRail Technical Marketing

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