vSphere

Can I still provision VMs when a vSAN Stretched Cluster site has failed? Part II

Duncan Epping · Dec 18, 2019 · Leave a Comment

3 years ago I wrote the following post: Can I still provision VMs when a VSAN Stretched Cluster site has failed? Last week I received a question on this subject, and although officially I am not supposed to work on vSAN in the upcoming three months I figured I could test this in the evening easily within 30 minutes. The question was simple, in my blog I described the failure of the Witness Host, what if a single host fails in one of the two “data” fault domains? What if I want to create a snapshot for instance, will this still work?

So here’s what I tested:

vSAN Stretched Cluster
4+4+1 configuration
- Meaning, 4 hosts in each “data site” and a witness host, for a total of 8 hosts in my vSAN cluster
Create a VM with cross-site protection and RAID-5 within the location

So I first failed a host in one of the two data sites. When I fail the host, the following is what happens when I create a VM with RAID-1 across sites and RAID-5 within a site:

Without “Force Provisioning” enabled the creation of the VM fails
When “Force Provisioning” is enabled the creation of the VM succeeds, the VM is created with a RAID-0 within 1 location

Okay, so this sounds similar to the originally described scenario, in my 2016 blog post, where I failed the witness. vSAN will create a RAID-0 configuration for the VM. When the host returns for duty the RAID-1 across locations and RAID-5 within each location is then automatically created. On top of that, you can snapshot VMs in this scenario, the snapshots will also be created as RAID-0. One thing to mind is that I would recommend removing “force provisioning” from the policy after the failure has been resolved! Below is a screenshot of the component layout of the scenario by the way.

I also retried the witness host down scenario, and in that case, you do not need to use the “force provisioning” option. One more thing to note. The above will only happen when you create a RAID configuration which is impossible to create as a result of the failure. If 1 host fails in a 4+4+1 stretched cluster you would like to create a RAID-1 across sites and a RAID-1 within sites then the VM would be created with the requested RAID configuration, which is demonstrated in the screenshot below.

Project nanoEDGE aka tiny vSphere/vSAN supported configurations!

Duncan Epping · Oct 10, 2019 · 10 Comments

A few weeks ago VMware announced Project nanoEDGE on their blog virtual blocks. I had a whole bunch of questions the following days from customers and partners interested in understanding what it is and what it does. I personally prefer to call project nanoEDGE “a recipe”. In the recipe, it states which configuration would be supported for both vSAN as well as vSphere. Lets be clear, this is not a tiny version of VxRail or VMware Cloud Foundation, this is a hardware recipe that should help customers to deploy tiny supported configurations to thousands of locations around the world.

Project nanoEDGE is a project by VMware principal system engineer Simon Richardson. The funny thing is that right around the time Simon started discussing this with customers to see if there would be interest in something like this, I had similar discussions within the vSAN organization. When Simon mentioned he was going to work on this project with support from the VMware OCTO organization I was thrilled. I personally believe there’s a huge market for this. I have had dozens of conversations over the years with customers who have 1000s of locations and are currently running single-node solutions. Many of those customers need to deliver new IT services to these locations and the requirements for those services have changed as well in terms of availability, which makes it a perfect play for vSAN and vSphere (with HA).

So first of all, what would nanoEDGE look like?

As you can see, these are tiny “desktop alike” boxes. These boxes are the Supermicro E300-9D and they come in various flavors. The recipe currently explains the solution as 2 full vSAN servers and 1 host which is used for the vSAN Witness for the 2 node configuration. Of course, you could also run the witness remotely, or even throw in a switch and go with a 3 node configuration. The important part here is that all used components are on both the vSphere as well as the vSAN compatibility guide! The benefit of using the 2-node approach is the fact that you can use cross-over cables between the vSAN hosts and avoid the cost of a 10GbE Switch as a result! So what is in the box? The bill of materials is currently as follows:

3x Supermicro E300-9D-8CN8TP
- The box comes with 4x 1GbE NIC Port and 2x 10GbE NIC Port
- 10GbE can be used for direct connect
- It has an Intel® Xeon® processor D-2146NT – 8 cores
6 x 64GB RAM
3 x PCIe Riser Card (RSC-RR1U-E8)
3 x PCIe M.2 NVMe Add on Card (AOC-SLG3-2M2)
3x Capacity Tier – Intel M.2 NVMe P4511 1TB
3x Cache Tier – Intel M.2 NVMe P4801 375GB
3x Supermicro SATADOM 64GB
1 x Managed 1GbE Switch

From a software point of view the paper lists they tested with 6.7 U2, but of course, if the hardware is on the VCG for 6.7 U3 than it will also be supported to run that configuration. Of course, the team also did some performance tests, and they showed some pretty compelling numbers (40.000+ read IOPS and close to 20.000 write IOPS), especially when you consider that these types of configurations would usually run 15-20 VMs in total. One thing I do want to add, the bill of materials lists M.2 form factor flash devices, this allows nanoEdge to avoid the use of the internal unsupported AHCI disk controller, this is key in the hardware configuration! Do note, that in order to fit two M.2 devices in this tiny box, you will need to also order the listed PCIe Riser Card and the M.2 NVMe add on card, William Lam has a nice article on this subject by the way.

There are many other options on the vSAN HCL for both caching as well as capacity, so if you prefer to use a different device, make sure it is listed here.

I would recommend reading the paper, and if you have an interest in this solution please reach out to your local VMware representative for more detail/help.

Capacity Overview in vSAN 6.7 U3

Duncan Epping · Sep 20, 2019 · Leave a Comment

I just wanted to do a short post before the weekend, in vSAN 6.7 U3 there’s a great capacity overview screen. It shows a couple of things, first of all, it provides a simple bar that shows “data written”, “reserved space” and “free space”. The second section provides you the ability to figure out what happens to your capacity consumption if you would change the policy on all VMs. The third section gives you a nice breakdown of the capacity per category and a great circular diagram which shows immediately what kind of data is consuming your capacity. Very useful!

VMworld Reveals: Armed and Ready (ESXi on ARM, #OCTO2944BU)

Duncan Epping · Sep 9, 2019 · 7 Comments

At VMworld, various cool new technologies were previewed. In this series of articles, I will write about some of those previewed technologies. Unfortunately, I can’t cover them all as there are simply too many. This article is about ESXi on ARM, which was session OCTO2944BU. For those who want to see the session, you can find it here. This session was presented by Andrei Warkentin and Daniel Beveridge. Please note that this is a summary of a session which is discussing a tech preview, these features may never be released, and this preview does not represent a commitment of any kind, and this feature (or it’s functionality) is subject to change. Now let’s dive into it, what is VMware doing with ARM?

First of all, what caught my interest in this session was the fact that Hivecell was mentioned. Hivecell is a rather unique solution which allows you to stack ARM hosts. What is unique about that? Well when I say stack, I mean stack in the physical sense. The interesting part here is that only the first node will need to have power and networking cables, and the rest will receive power and networking through a magnetic link. William wrote about it extensively, so go here to read more about these guys. Really cool solution if you ask me.

The session started with an intro to ARM and the various use cases. I wrote about that extensively when Chris Wolf and Daniel discussed that at VMworld 2018. So I am not going to reiterate that either, just click the link to figure out why ARM could be interesting. What was new in this session then compared to last year? Well they showed a couple of things which I have not seen shown in public before.

First thing that was discussed was the fact that VMware is looking to support the AWS ARM instances (A1 instance) which were introduced a while ago. The plan is to not only support ARM, but also support Elastic Network Interfaces(ENI) and Elastic Block Storage(EBS). All of it managed through vCenter Server of course. VMware is now looking for early validation customers and partners.

VMworld Reveals: Disaster Recovery / Business Continuity enhancements! (#HCI2894BU and #HBI3109BU)

Duncan Epping · Sep 4, 2019 · 1 Comment

At VMworld, various cool new technologies were previewed. In this series of articles, I will write about some of those previewed technologies. Unfortunately, I can’t cover them all as there are simply too many. This article is about enhancements in the business continuity/disaster recovery space. There were 2 sessions where futures were discussed, namely HCI2894BU and HBI3109BU. Please note that this is a brief summary of those sessions, and these are discussing a Technical Preview, these features/products may never be released, and these previews do not represent a commitment of any kind, and this feature (or it’s functionality) is subject to change. Now let’s dive into it, what can you expect for disaster recovery in the future?

The first session I watched was HCI2894BU, this was all about Site Recovery Manager. I think the most interesting part is the future support for Virtual Volumes (vVols) for Site Recovery Manager. It may sound like something simple, but it isn’t. When the version of SRM ships that supports vVols keep in mind that your vVol capable storage system also needs to support it. At day 1 HPe Nimble, HPe 3PAR and Pure Storage will support it and Dell EMC and NetApp are actively working on support. The requirements are that the storage system needs to be vVols 2.0 compliant and support VASA 3.0. Before they dove into the vVols implementation, some history was shared and the current implementation. I found it interesting to know that SRM has over 25.000 customers and has protected more than 3.000.000 workloads over the last decade.