Virtualization-vmware-vsphere

Vmotion: Online host location change

The biggest feature of online migration of virtual machines in order to change their host location is that "Virtual Machine applications will not be interrupted throughout the migration process". VMWare has always been proud of this feature, especially before Citrix xenserver and Microsoft hyper-V introduced similar features, most enterprises first consider using vmotion in server virtualization projects, in addition, high availability features such as Drs are based on vmotion.

Vmotion solves planned downtime. For example, if your machine needs to upgrade the memory, you can first migrate the VM on the ESX Server, and then power off and upgrade the memory. But your business (VM) does not pause.
Vmotion is a planned migration (hot migration ). Simply put, virtual machines on esxi/ESX servers are automatically, semi-automatically, or manually (in combination with DRS) migrated to other esxi/ESX hosts in the cluster, the whole process does not require downtime, and the system will not be interrupted (some people are used to calling it seamless migration ).

Storage vmotion: online storage location change

This is a storage migration feature launched by VMware in ESX 3.5 and later versions. It is used to change the storage location when the VM is started. Like vmotion, the entire migration process is transparent to users, the application will not be interrupted; it seems that other virtualization vendors have not released the corresponding functions.

Vsphere haYou can restart a VM to provide basic protection for the VM when the host fails.

Ha solves unexpected server downtime. For example, if your ESX host suddenly crashes, the VM on this ESX host will be restarted on other ESX hosts to ensure business continuity.
This ensures that the overall downtime does not exceed 5 to 10 minutes and can be protected by unexpected downtime (Vm restart is required ). Ha requires 13 S + 5 S + 350 s = 368 s downtime, of which S is the VM startup time, the specific environment time is different, 13 s is the HA heartbeat Interval check, 5 seconds is Ha's own isolated Detection

Vsphere Fault ToleranceMore advanced availability is provided, allowing users to protect any virtual machine to prevent data loss, transactions, or connections in the event of a host failure.
In fact, ft is rarely used in daily virtualization usage. One is serious waste of resources, and the other is that a single virtual CPU cannot meet business needs, third, only a few applications require low configuration but high availability.
FT: Fault Tolerance (fault tolerance ). The out-of-the-box downtime protection feature is further enhanced by implementing the abnormal esxi/ESX host's FT-protected Virtual Machine without restarting on the basis of HA, it can run normally on other esxi/ESX hosts in the cluster without interruption. It is often referred to as "unplanned 0 down" protection. (FT currently requires a single Virtual Disk in vcpu and eagerzeroed thick mode ).

Multiple concepts that are easy to confuse and ignore in VMware vsphere knowledge

Virtualization-vmware-vsphere