Yellow Bricks

by Duncan Epping

VMware

Does a vSAN IO Limit impact resync traffic?

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A question just came in, and I figured other people may have the same question so I would share it. The question was if a vSAN IO limit would impact resync traffic or for instance SvMotion? In this case the customer defines limits within each policy to ensure VMs do not interfere with other VMs or excessively uses IO resources. Especially in cloud environments this can be useful, or when running production and test/dev on the same cluster. The concern, of course, was if this limit would impact for instance recovery times after a failure. Because you can imagine that a limit of 50 IOPS would be devastating when a VM (or multiple VMs) need to have objects resynced.

The answer is simple: no, the IO limit specified within a policy does not impact resync traffic (or SvMotion for that matter). It only applies to Guest IO to a VMDK, namespace or swap object. Which means that it is safe to set limits when it comes to recovery times.

Major vSAN Milestone: 20K customers – Celebrating by dropping the price of our book with 50%!

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I haven’t done one of these in a while, and as it is a question that comes up regularly during customer conversations I figured I would share a nice quote from the VMware earnings call. But before I do I want to thank every VMware employee, partner and customer who helped us reaching this major milestone. Sometimes customers ask how invested VMware is in storage, well very invested. Determined to remain the number 1 player in the hyperconverged and hybrid cloud world, and the below numbers show why!

vSAN license bookings grew over 50% year-over-year in Q1 with a total customer count growing to over 20,000. (seekingalpha.com)

Yes, that is 20,000 customers indeed. Actually, more than 20k customers. Which, again, is a great success and would not have been possible without the help from you guys. So to thank all of you Cormac and I have decided to lower the price of our book temporarily. For 1 week, today until Friday the 7th, we have lowered the price of the book by ~50%. This means that on the Amazon US store the book will be 20 USD for the paper version, and only 5 USD for the ebook. So pick it up! (It may take a day for the price change to reach some of the Amazon stores…) Please note, as an Amazon Associate I earn from below qualifying purchases.

<UPDATE>

It seems the price has been pushed down to all “local” amazon websites. So go to your local website and pick up the book for 50% of the previous price. Links to most localized websites here:

Site locality in a vSAN Stretched Cluster?

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On the community forums, a question was asked around the use of site locality in a vSAN Stretched Cluster. When you create a stretched cluster in vSAN you can define within a policy how the data needs to be protected. Do you want to replicate across datacenters? Do you want to protect the “site local data” with  RAID-1 or RAID-5/6? All of these options are available within the UI.

What if you decide to not stretch your object across locations, is it mandatory to specify which datacenter the object should reside in?

The answer is simple: no it is not. The real question, of course is, would be: should you define the location? Most definitely! If you wonder how to do this, simplicy specify it within the policy you define for these objects as follows:

The above screenshot is taken from the H5 client, if you are still using the Web Client it probably looks slightly different (Thanks Seamus for the screenshot):

Why would you do this? Well, that is easy to explain. When the objects of a VM get provisioned the decision will be made per object where to place it. If you have multiple disks, and you haven’t specified the location, you could find yourself in the situation where disks of a single non-stretched VM are located in different datacenters. This is, first of all, terrible for performance, but maybe more importantly also would impact availability when anything happens to the network between the datacenters. So when you use site locality for non-stretched VMs, make sure to also configure the location so that your VM and objects will align as demonstrated in the below diagram.

 

VMware RADIO Fun Run 2019

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William Lam and I have been organizing a “running” event at a VMware internal event called RADIO. RADIO is our yearly R&D Innovation Offsite and is usually held in San Francisco. What is this run? Well basically it started many years ago (7 or 8?) with a group of 4-5 runners meeting up at 6:00 AM to go for a run. The group organically grew the next year to about 7 or 8 and I figured I could potentially do something similar to the VMworld RUN I organized many years ago. So the year after we asked the RADIO team if we could have it listed on the agenda officially, they looked at us a bit strange as they didn’t expect anyone to wake up at 05:30 to go for a 5KM or 10KM run at 06:00 AM. I guess they forgot that many of us fly in from a different country, and as such are jetlagged and will be awake for hours by then. The first official run had 15-20 runners, followed by 25 the next year and it steadily grew. It wasn’t just William and I, of course, organizing this, we had folks like Chris Wolf, for instance, helping out.

The past two years we stepped up our game, as the numbers started growing, and we managed to get funding for running shirts and hats and started working with the event team to get it a bit more structured. Why? Well, when there are 75-80 people running in a city like San Francisco you need to stand out and you can’t just walk outside and run, things need to be a bit more structured. This year we had about 120 people joining on the run. VMware employees from different business units and different countries. A great way to meet people you normally wouldn’t meet, especially not in a setting like this. For instance, we had our Chief People Officer joining last year, we bumped into Michael Dell this year and of course our global field CTO Chris Wolf also joined again. But that is not the goal, the goal is to get to meet people you normally would not meet. I for instance also happened to run next to a developer who worked on VASA and we got to discuss an issue I was experiencing, which subsequently then got fixed. Pretty cool.

Anyway, I just wanted to share some pictures of the run, as it may get you thinking about organizing something like this as well for a company event! It is fun and worth the effort! If you participated and are reading this, thanks for joining, hope to see you next year! And of course, everyone who helped to organize, thanks!

I want vSphere HA to use a specific Management VMkernel interface

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This comes up occasionally, customers have multiple Management VMkernel interfaces and see vSphere HA traffic on both of the interfaces, or on the incorrect interface. In some cases, customers use the IP address of the first management VMkernel interface to connect the host to vCenter and then set an isolation address that is on the network of the second management VMkernel so that HA uses that network. This is unfortunately not how it works. I wrote about this 6 years ago, but it never hurts to reiterate as it came up twice over the past couple of weeks. The “management” tickbox is all about HA traffic. Whether “Management” is enabled or not makes no difference for vCenter or SSH for instance. If you create a VMkernel interface without the Management tickbox enabled you can still connect to it over SSH and you can still use the IP to add it to vCenter Server. Yes, it is confusing, but that is how it works.

If you want the interface to not be used by vSphere HA, make sure to untick “Management”. Note, this is not the case for vSAN, with vSAN automatically the vSAN network is used by HA. This only pertains to traditional, non-vSAN based, infrastructures.