VxRail ACE

February 4, 2020

One of the key areas of focus for VxRail ACE (Analytical Consulting Engine) is active multi-cluster management.  With ACE, users have a central point to manage multiple VxRail clusters more conveniently.  System updates for multiple VxRail clusters is one activity where ACE greatly benefits users.  It is a time-consuming operation that requires careful planning and coordination.   In the initial release of ACE, users were able to facilitate transfer of update bundles to all their clusters with ACE acting as the single control point versus logging onto every vCenter console to do the same activity.  That can save quite a bit of time.

On-demand pre-upgrade cluster health checks

In the latest ACE update, users can now run on-demand health checks prior to upgrading to find out if their cluster is ready for a system update.  By identifying which clusters are ready and which ones are not, users can more effectively schedule their maintenance windows in advance.  It allows them to see which clusters require troubleshooting and which ones can start the update process.  In ACE, on-demand cluster health checks are referred to as a Pre-Check.  

For more information about this feature, you can check out this video: https://vxrail.is/aceupdates

Deployment types

Another feature that came out with this update is the identification of the cluster deployment type.   This means ACE will now display whether the cluster is a standard VxRail cluster in a VMware Validated Design deployment, in a VMware Cloud Foundation on VxRail deployment used in Dell Technologies Datacenter-as-a-Service, a 2-node vSAN cluster, or in a stretched cluster configuration.

Daniel Chiu, VxRail Technical Marketing

LinkedIn

Performance, endurance, and all without a price jump!

There is a saying that “A picture paints a thousand words” but let me add that a “graph can make for an awesome picture”.

Last August we at VxRail worked with ESG on a technical validation paper that included, among other things, the recent addition of Intel Optane NVMe drives for the vSAN caching layer. Figure 3 in this paper is a graph showing the results of a throughput benchmark workload (more on benchmarks later). When I do customer briefings and the question of vSAN caching performance comes up, this is my go-to whiteboard sketch because on its own it paints a very clear picture about the benefit of using Optane drives – and also because it is easy to draw.

In the public and private cloud, predictability of performance is important, doubly so for any form of latency. This is where caching comes into play, rather than having to wait on a busy system, we just leave it in the write cache inbox and get an acknowledgment. The inverse is also true. Like many parents I read almost the same bedtime stories to my young kids every night, you can be sure those books remain close to hand on my bedside “read cache” table. This write and read caching greatly helps in providing performance and consistent latency. With vSAN all-flash there no longer any read cache as the flash drives at the capacity layer provide enough random read access performance… just as my collection of bedtime story books has been replaced with a Kindle full of eBooks. Back to the write cache inbox where we’ve been dropping things off – at some point, this write cache needs to be empty, and this is where the Intel Optane NVMe drives shine. Drawing the comparison back to my kids, I no longer drive to a library to drop off books. With a flick of my finger I can return, or in cache terms de-stage, books from my Kindle back to the town library - the capacity drives if you will. This is a lot less disruptive to my day-to-day life, I don’t need to schedule it, I don’t need to stop what I’m doing, and with a bit of practice I’ve been able to do this mid story Let’s look at this in actual IT terms and business benefits.

To really show off how well the Optane drives shine, we want to stress the write cache as much as possible. This is where benchmarking tools and the right knowledge of how to apply them come into play. We had ESG design and run these benchmarking workloads for us. Now let’s be clear, this test is not reflective of a real-world workload but was designed purely to stress the write cache, in particular the de-staging from cache to capacity. The workload that created my go-to whiteboard sketch was the 100% sequential 64KB workload with a 1.2TB working set per node for 75 minutes.

The graph clearly shows the benefit of the Optane drives, they keep on chugging at 2,500MB/sec of throughput the entire time without dropping a beat. What’s not to like about that! This is usually when the techie customer in the room will try to burst my bubble by pointing out the unrealistic workload that is in no way reflective of their environment, or most environments… which is true. A more real-world workload would be a simulated relational database workload with a 22KB block size, mixing random 8K and sequential 128K I/O, with 60% reads and 40% writes, and a 600GB per node working set, which is quite a mouthful and is shown in figure 5. The results there show a steady 8.4-8.8% increase in IOPS across the board and a slower rise in latency resulting in a 10.5% lower response time under 80% load. 

Those of you running OLTP workloads will appreciate the graph shown in figure 6 where HammerDB was used to emulate the database activity of a typical online brokerage firm. The Optane cache drives under that workload sustained a remarkable 61% more transactions per minute (TPM) and new orders per minute (NOPM). That can result in significant business improvement for an online brokerage firm who adopts Optane drives versus one who is using NAND SSDs.

When it comes to write cache, performance is not everything, write endurance is also extremely important. The vSAN spec requires that cache drives be SSD Endurance Class C (3,650 TBW) or above, and Intel Optane beats this hands down with an over tenfold margin at 41 PBW (41,984 TBW). The Intel Optane 3D XPoint architecture allows memory cells to be individually addressed in a dense, transistor-less, stackable design. This extremely high write endurance capability has let us spec a smaller sized cache drive, which in turn lets us maintain a similar VxRail node price point, enabling you the customer to get more performance for your dollar. 

What’s not to like? Typically, you get to pick any two; faster/better/cheaper. With Intel Optane drives in your VxRail you get all three; more performance and better endurance, at roughly the same cost. Wins all around!

Author: David Glynn, Sr Principal Engineer, VxRail Tech Marketing

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