This article only discusses the differences between ESX 3 and ESX 4. In addition, VMware ESXi is also included in the table if necessary. In many ways, ESXi is the same as ESX. The VMware ESX/ESXi architecture overview is described above. The main difference is how ESXi starts, and ESXi lacks a mature service console. Unless otherwise specified, hereinafter the same comparison made for ESX and ESXi.
Core Vmkernel difference is
ESX VMkernel, and future enhancements are source Improve this very important subsystem. The new vmkernel supports new and different guest operating systems and is upgraded to support the latest version of the service console and drive interaction. Vmkernel looks similar to the Linux kernel, but it is not a Linux kernel. The most interesting similarity is the way the kernel is loaded, but the list of supported modules has changed. Table 2.1 shows the standard modules loaded by each version of ESX. Table 2.1
module version difference (using Proliant DL380 rack server, a command using the following result vmkload -b)
in ESX 3 separated the service console is vmkernel Physically, there is still a considerable amount of bleed-through. In ESX 3.5, this penetration has almost been eliminated. Third-party management agents need this penetration to properly control some hardware. However, in ESX 4, VMware introduced a new drive to handle the need to control the hardware, requiring almost no third-party management agents. These agents include Dell Openmanage and HP's Insight Management Agent (now supported by improved IPMI).
With the introduction of ESX 4, VMware abandoned some modules appear in earlier versions. If the devices supported by these modules are required for ESX installation, then you will not be able to upgrade to ESX. 4. Table 2.2 lists the devices that exist in ESX 3 but are obsolete in ESX 4, and in Table 2.3 Includes devices that exist in ESX 2.5 but are deprecated in ESX 3. Developers of ESX 4 prefer to choose stylish hardware, so the original PCI or PCI-X hardware is deprecated. From a stability point of view, this is a good choice. Minimizing the number and types of devices that must be supported enables the development team to focus on providing quality assurance for the devices that need to be supported. FIG
2.2 ESX 4 discarded device
FIG ESX 3 2.3 ESX3 supported in the discarded devices supported by ESX 2.5
should ESX 3 and ESX 4 Some other different vmkernel features are explained. The first change is to open up the internal architecture of vmkernel through well-defined APIs, allowing third parties to add corresponding elements to the vmkernel. These APIs include vNetwork, vStorage, vCompute, and VMsafe.
vStorage is a new name for the Virtual Disk Development Kit (vDDK), which is available from VMware on ESX 3. Other APIs are new. And added the main features.
In addition to the above changes, starting with ESX 4, vmkernel is 64-bit and supports up to 1TB of memory and 320 virtual machines, these virtual machines can use up to 512 virtual CPUs.
< B> ESX guide difference
simple, the service console has been based on a 32-bit Red Hat Enterprise Linux Enterprise Server upgrade to 3 Update 8 from 64-bit Red Hat Enterprise Linux Enterprise Server 5.1. ESX is by no means a complete GNU/Linux distribution. Technically, ESX is not Linux at all, because the vmkernel interacts with the hardware, and the service console runs inside the virtual machine. Legally, vmkernel is not Linux because it is proprietary. Although the service console is a variant of GNU/Linux, it is just a management device and not an ESX operating system.
Although the version of the service console has changed, the rules for "no updates to Red Hat" have not changed. All updates to the service console should come from VMware only, which is critical. Consider the following: ESX includes only one CD-ROM, and the official version of RHEL 5 supports up to five CD-ROMs. Therefore, the server console does not have the same features as RHEL and should not be considered identical. For RHEL 5, the way to configure the system is to use the system-config-script, which does not apply to ESX. Instead, there is a series of esxcfg-scripts in ESX that are not identical to Red Hat's original scripts. correspond.
However, esxcfg- scripts to new management tools and vSphere Client corresponds well. You can configure the ESX host directly from the client, or you can use the VMware vCenter server. Although you still provide a web-based interface, you cannot configure an ESX host or create a virtual machine through the web interface.
ESX core 4 is dedicated, and VMkernel modified by RHEL 5, the core operation in the service console can not be only a dedicated core Linux.ESXi 4 vmkernel. By modifying the generic kernel so The service console can manage the ESX hypervisor.ESX 4 service console only sees the hardware presented or directly through the vmkernel, and the service console does not interact directly with the hardware unless a passthrough device is used. Modifying ESX is limited to adding or removing device drivers to the vmkernel and controlling virtual machines and virtual switch objects running in the vmkernel.
In versions prior to ESX 3, vmkernel will be loaded after the service console is fully booted, and the vmkernel will take a collection of all PCI devices controlled by the kernel options. A change has occurred in ESX 3. First load the vmkernel, then the service console. The service console runs inside a proprietary virtual machine that has more privileges than a standard virtual machine. In ESX 3, the service console is installed on a local disk that accesses the local disk through a RAW pass-through SCSI device. In ESX 4, another change has been made, that is, RAW pass-through SCSI devices are no longer used. Instead, the GNU/Linux environment is located in a virtual machine disk (VMDK) file. This change further emphasizes the difference between hypervisor and GNU/Linux. So repeat it again: the hypervisor is non-Linux (notLinux).