Virtualization (5): vsphere high-availability cluster and fault tolerance

Vsphere advanced features can be achieved only when vcenter server and shared storage are supported. Vsphere advanced features include vmotion, storage vmotion, vsphere ha, vsphere DRS, storage DRS, and vsphere fault tolerance.

1. vmotion

Vmotion is a function that can be used to migrate a running Virtual Machine from one esxi host to another esxi host without interrupting the service.

2. Storage vmotion

 

This function is used to move the disks and configuration files of running virtual machines from one data storage to another without interrupting the service.

3. vsphere ha

A function that enables a cluster to have high Availablity. If a host fails, all virtual machines running on the host will be restarted immediately on other hosts in the same cluster.
When you enable the vsphere ha feature of a cluster, specify the number of hosts you want to restore.

VMware ha restarts the virtual machine when the host fails to provide the basic level of inclusion for the virtual machine. VMware fault tolerance provides higher levels of availability, allowing users to protect any virtual machine to prevent data, transactions, and other faults on the host.
Fault Tolerance uses VMware vlockstep technology on the esxi host platform to provide continuous availability. This process is completed by ensuring that the status of the Primary and Secondary VMS is the same at any point in time when the VM commands are executed. Vlockstep allows the Primary and Secondary VMS to execute x86 commands in the same sequence. The primary VM captures all events and replays them on the secondary VM.
If the host of the primary virtual machine is allowed to fail, transparent failover will occur.

4. vsphere Drs

Vsphere DRS is a feature that helps improve resource allocation and feature consumption between all hosts and resource pools. Resource usage of all hosts and virtual machines in the vsphere DRS mobile phone cluster, and the placement suggestions and load balancing functions (that is, drs will try to improve the resource utilization in the cluster by executing automatic migration-vmotion of virtual machines or providing recommendations for Virtual Machine migration ).

5. Storage Drs

Storage DRS is a function used to manage multiple data storage as a single data storage cluster. You can allocate a virtual disk to a data storage cluster. The stored DRS will find the corresponding data storage for it. The Load balancer is responsible for initial placement and subsequent migration based on the measurement. The storage space balance and I/O balance can minimize the risk of insufficient space and I/O Bottlenecks of virtual machine performance.

6. vsphere Fault Tolerance

Vsphere ft ensures continuous availability of virtual machines by creating and maintaining secondary virtual machines that are the same as the primary virtual machines and can be replaced at any time during failover.

Currently, the only fault tolerance disadvantage of VMware is that a fault-tolerant virtual machine can allocate only one CPU, but does not support multiple CPUs.

7. Create a cluster