Download Vsphere Hypervisor

[Silvina Spindler]

Wehave a physical machine with 500GB of storage, enough CPU (4 x 2GHz Intel Xeon) and 16 GB of RAM. I would like to know the amount of memory that should be reserved for the hypervisor. We come from using VMware Server, and maybe this consideration is not necessary in vSphere.

It's possible to set a reservation in vSphere but you shouldn't need to do this under normal circumstances. You should not need to make any automatic memory reservation on ESXi for the hypervisor. It will preserve sufficient memory for its usage by itself. Note that vSphere is (from the ground up) a completely different beast to VMWare's other products. There's little to zero common code there. So tweaks applied to workstation or server are almost universally irrelevant in a vSphere environment.

That said, if you over-allocate your RAM and one of the VMs demands more than the host can provide, your VMs will start swapping memory to disk (super slow!). So long as your VMs don't attempt to consume all of their allocated memory (typically only certain products such as SQL server will behave in this manner), you can allocate up to (and over) 100% of the host's RAM (since they'll never really use it all, anyway).

If you want to play it safe, leave at least 2Gb unallocated and carve the remaining 14Gb between your VMs however you like. Assuming you end up with 2 VMs with 6 to 8Gbs of RAM each, the extra RAM overhead per VM will be 300 to 400Mb.

Above all though, my overriding advice is this: Do not tweak any settings or alter any defaults in any way on the host or VM configurations, unless there's a very specific need you have which is clearly solved by a particular setting. Don't make any 'sounds like a good idea' changes out of the box, it's a really fast way to get yourself into 'now I have lots of strange issues and nobody can help because my system's configuration is nothing like anyone else's system configuration'.

My understanding is that "vSphere" is a brand name for the suite of software products, that allow an entity (enterprise, hosting co. etc.) to create cloud-computing infrastructure, using virtualization technologies, but at the same time giving tools to configure and manage cluster of hosts running hypervisor and VMs (on the hypervisor).

Also, my understanding is vSphere Hypervisor includes ESXi for the server virtualization, but bundled with just enough management tools to manage a single instance of ESXi, i.e. it is not cluster-aware, and can manage only 1 host. That single host, however can run many VMs.

Once upon a time, pursuing a virtualization solution was relatively easy due to a limited number of products and solutions on the market. Today, there has been an explosion of virtualization vendors, with countless products and features available. This adds complexity for decision-makers and data center managers hoping to make a fast and informed decision that best suits their business requirements.

Developed by VMware, vSphere is a cloud computing virtualization platform. It should not be thought of as a product, rather a product family containing supportive software and management tools. Another way of looking at it is that vSphere is a suite of virtualization solutions that includes vCenter, ESXi, vRealized Operations, and more.

The core ability of vSphere is the centralized management of your virtual machines and virtual environment. vSphere offers a very wide range of functionality, although this will vary from organization to organization based on the components of the suite each uses. Some of the most important functionality offered by vSphere include the following:

VMware ESXi is yet another component of vSphere. It is also one of the most popular components because it delivers the core virtualization services organizations need. It is a bare-metal hypervisor and delivers a host of critical capabilities and features.

ESXi and vCenter are two different components of vSphere. vCenter is advanced server management software usually deployed as a pre-configured Linux virtual machine, while ESXi is a virtualized hypervisor that is installed only on physical machines. These are both part of the vSphere solution.

Like vCenter, ESXi is a component solution designed to operate within the vSphere suite. ESXi is designed to create and manage multiple virtual machines on a single physical server, while vSphere is an entire solution designed to improve your IT resilience by leveraging virtualization with your physical IT assets.

This is a huge deal for the VMware ecosystem. It is a bit different in scope between this and the Red Hat Goes Full IBM and Says Farewell to CentOS transition. The real reason for the free version of the free vSphere hypervisor was to get folks onboarded to the VMware ecosystem. Now, anyone looking to get into the VMware ecosystem will have to pay, while other options are going to be free. Keep in mind, due to its use at cloud providers like AWS, Linux KVM virtual machines that underpin offerings like Proxmox VE have enormous usage.

Going forward, removing a free option creates a skill gap, much like exists today for mainframe admins. New college grads are unlikely to graduate having used mainframes. Many will have used cloud or Linux servers and will enter the workforce with at least some experience. Further, those who are getting on-the-job training on mainframes are those working in the industries and handfuls of companies still using them. Five years into a career there are folks who have used mainframes, and those who have not. Since the mainframe market is smaller in terms of numbers of systems sold each year, that creates an exclusive set of folks who have experience in a minority technology.

Of course, these transitions take time. Mainframes were declared dead decades ago and are still being used today. Regular STH readers have probably already executed on a transition plan or have one in the works if needed since we covered what would happen in 2022 in Broadcom Agrees to Purchase VMware Shaking Up the Industry. If you were relying upon VMware vSphere free edition, then the message is clear. It is time to migrate to either a paying customer or to migrate to another solution.

Agreed, this will drive folks to other solutions and limit options for off-line skill improvement. If they are going down this path, they need to make the VMware Advantage subscriptions cheaper and easier to get. And also include free license access in the new subscription license model for IT employees.

Now this will just push more people into cloud and kubernetes. Whatever you do on VMware you can do elsewhere, if licensing costs is higher than the investment of migrating. What is the business model here?

VMware ESXi (formerly ESX) is an enterprise-class, type-1 hypervisor developed by VMware, a subsidiary of Broadcom, for deploying and serving virtual computers. As a type-1 hypervisor, ESXi is not a software application that is installed on an operating system (OS); instead, it includes and integrates vital OS components, such as a kernel.[5]

After version 4.1 (released in 2010), VMware renamed ESX to ESXi. ESXi replaces Service Console (a rudimentary operating system) with a more closely integrated OS. ESX/ESXi is the primary component in the VMware Infrastructure software suite.[6]

The name ESX originated as an abbreviation of Elastic Sky X.[7][8] In September 2004, the replacement for ESX was internally called VMvisor, but later changed to ESXi (as the "i" in ESXi stood for "integrated").[9][10]

ESX runs on bare metal (without running an operating system)[11] unlike other VMware products.[12] It includes its own kernel. In the historic VMware ESX, a Linux kernel was started first[13] and then used to load a variety of specialized virtualization components, including ESX, which is otherwise known as the vmkernel component.[14] The Linux kernel was the primary virtual machine; it was invoked by the service console. At normal run-time, the vmkernel was running on the bare computer, and the Linux-based service console ran as the first virtual machine. VMware dropped development of ESX at version 4.1, and now uses ESXi, which does not include a Linux kernel at all.[15]

The vmkernel handles CPU and memory directly, using scan-before-execution (SBE) to handle special or privileged CPU instructions[17][18]and the SRAT (system resource allocation table) to track allocated memory.[19]

Access to other hardware (such as network or storage devices) takes place using modules. At least some of the modules derive from modules used in the Linux kernel. To access these modules, an additional module called vmklinux implements the Linux module interface. According to the README file, "This module contains the Linux emulation layer used by the vmkernel."[20]

These drivers mostly equate to those described in VMware's hardware compatibility list.[21] All these modules fall under the GPL. Programmers have adapted them to run with the vmkernel: VMware Inc. has changed the module-loading and some other minor things.[20]

In ESX (and not ESXi), the Service Console is a vestigial general purpose operating system most significantly used as bootstrap for the VMware kernel, vmkernel, and secondarily used as a management interface. Both of these Console Operating System functions are being deprecated from version 5.0, as VMware migrates exclusively to the ESXi model.[22]The Service Console, for all intents and purposes, is the operating system used to interact with VMware ESX and the virtual machines that run on the server.

In the event of a hardware error, the vmkernel can catch a Machine Check Exception.[23] This results in an error message displayed on a purple diagnostic screen. This is colloquially known as a purple diagnostic screen, or purple screen of death (PSoD, c.f. blue screen of death (BSoD)).

Upon displaying a purple diagnostic screen, the vmkernel writes debug information to the core dump partition. This information, together with the error codes displayed on the purple diagnostic screen can be used by VMware support to determine the cause of the problem.

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