Rebuild / Resynchronization time is one of the things I have seen jump up and bite customers on the ankle over and over… When you distribute your storage across multiple hosts in a hperconverged cluster, the arithmetic and physics of migrating or copying data between hosts plays a critical role in the daily operations of that cluster. Putting hosts in maintenance mode or recovering from a failure both create circumstances that may require the cluster to move or copy large amounts of data between cluster hosts – and the length of time it takes to do so can have a material impact on the perceived efficiency or supportability of the solution. Continue reading
Posted in Best Practice, From the field, Hyperconverged Infrastructure (HCI), Virtualization - Server, vSAN
Tagged best-practice, cluster, HCI, howto, hyperconverged, Storage, Virtualization
Buckle in, this may be a long post….
I have been working recently with a customer that happens to have a large vSAN environment – indeed, one of the largest vSphere clusters I have encountered at 48 hosts – and as a result I have been doing a good bit of thinking about how to give guidance for this customer, what sort of recommendations VMware should be providing, and generally how to approach fault domains in a vSAN environment.
In this post, I hope to address some of the design considerations for building out a vSAN cluster with fault domains beyond what is addressed in VMware’s vSAN Design and Sizing Guide. Nonetheless, if you are not already familiar with how to size a vSphere cluster to include vSAN storage, that is a great place to start, and required reading, as far as I am concerned. Continue reading
Recently a customer posed a question about what they were seeing in vSAN when they moved a virtual machine over to a vSAN datastore. Essentially, they were seeing vCenter report the VMDK as consuming more space than they had expected. I began to compose a response, but then realized I might be missing some things in my explanation myself, so I took the opportunity to leverage our Hands-On-Labs to do a little experimenting.
By the way, if you don’t already use the HOL, it’s a great resource for learning, experimenting, and understanding behavior…. there are a ton of products you can play with and it is all available through your web browser.https://hol.vmware.com
So I wanted to answer the following questions for my customer:
- How does the reporting of free / used space differ between vCenter and the guest operating system of a virtual machine?
- What is the difference – if any – between the utilization of capacity between a normal datastore and a vSAN datastore?
- What should we expect to see when the protection scheme used by vSAN changes?
I have had the privilege to begin to work with the Cloud Native Apps team at VMware a bit over the past couple months, and I am becoming more and more convinced that this is a topic and a trend that will be come more and more impactful as time passes.
There is much to be said (written) about the rise of Continuous Integration and Continuous Deployment (CI/CD), how DevOps is changing the way our customers go about the business of IT, and how applications are being written in new ways with new tools (think ‘microservices’). However, without getting bogged down by the noise created by everything that’s going on in the market, there are some fundamental truths we have to come to grips with… Continue reading
VMware recently released Photon OS – Tech Preview 2. You can find it here, along with some of their other open-source initiatives. This post is intends to (hopefully) introduce folks to Photon and demonstrate how easy it is to use as part of a larger solution.
Photon OS is an RPM-based Linux distribution built expressly to support containers and container-cluster frameworks, like Kubernetes and Mesos, and optimized to run on vSphere. Support for Docker, Rocket, and Pivotal Garden are built right into Photon OS, though only the binaries for Docker are included by default. What’s more, with the release of Tech Preview 2, the binaries for Kubernets and Mesos are built-in as well, making working with your favorite cluster resource scheduler easier than ever. You can read more about Photon OS here.
One thing to note, however, is that when you first install Photon OS, you have a choice of installation types – Micro, Minimal, Full, and something else named OS Tree, which I won’t go into now. The difference(s) between Micro, Minimal and Full are – as one would expect – in the packages and binaries that are included with each installation. For example, if I install a “minimal installation of Photon, take a look at the output of a couple of “list” commands in the console: Continue reading