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Editor to share with you how vSphere realizes the hot migration of virtual machines through vMotion. I hope you will get something after reading this article. Let's discuss it together.

In the real world, there will always be metabolism, and old machines can not escape the destruction of time, which requires the replacement of new machines, and vMotion is a unique technology developed by VMware to migrate running virtual machines from one server to another.

To achieve a hot migration, an external shared storage server is essential because both the source ESXi host and the target ESXi host must be able to access the virtual machine files, so the virtual machine configuration files must be migrated to external shared storage before the hot migration.

Openfiler is a free NAS/ISCSI SAN server system, which is mainly used to provide independent storage system for LAN hosts. Openfiler provides a variety of connection methods, including NFS, SMB, ISCSI, target and so on, which are generally managed through http. For small and medium-sized enterprises that want to build virtualization, it is the best tool for the provisiong phase.

VMotion is the foundation of all vSPhere advanced features and enables hot migration.

VMotion migration process (if an error occurs during the migration, the virtual machine will restore the original state and location):

1. When requesting vMotion migration, vCenter server verifies whether the virtual machine and the ESXi host are stable.

2. At this point, the source ESXi host clones the virtual machine memory to the new ESXi host

3. The source ESXi host records the memory information changed during cloning on the memory map (some people also become electrocardiograms).

4. When the memory data of the virtual machine is migrated to the new ESXi host, the source ESXi host will put the virtual machine in a static state, when the virtual machine cannot provide services (only for a second or two), and then clone the memory map to the new ESXi host. The time required for a static state is extremely short.

5. The new ESXi recovers the memory data according to the memory map. After completion, the memory of the two ESXi hosts is exactly the same for this virtual machine.

6. Finally, run the virtual machine on the new ESXi host and delete the memory data in the source ESXi host (automatically delete without action)

Compatibility requirements for running vMotion:

1. It is not allowed to connect devices that can only be recognized by a single ESXi host, such as optical drive, floppy drive, etc.

2. It is not allowed to connect to a virtual switch without a physical network.

3. The migrated virtual machine must be stored in external shared storage, and all ESXi hosts can access it.

4. The ESXi host has at least 1 gigabit network card for vMotion.

5. If you use a standard switch, you must ensure that the port group network labels of all ESXi hosts are consistent.

6. The CPU vendor used by all ESXi hosts must be consistent (Intel or AMD)

Case environment:

Openfiler image:

Https://pan.baidu.com/s/1xHNHGkuWpux0o59v7_RPdw

Extraction code: 45vp

You can also download the latest version of ISO image in www.openfiler.com

First install the openfiler system:

Restart the system after installation:

Next, configure external shares:

Add a security access control list that allows access to the openfiler system:

Then add the shared logical volume:

Enable iscsi protocol:

Enter the VCenter web client configuration to connect to shared storage and create a port group:

Add a port group:

Add an iscsi adapter:

The target host configuration is the same

Once these are ready, you can begin the migration:

Wait for the virtual machine to migrate:

Use the ping command to perform a dead ping and observe the status of the virtual machine migration:

There are delays and one or two packet losses during the migration process:

Wait for the progress bar to complete, the migration will be over!

After reading this article, I believe you have a certain understanding of "how vSphere realizes virtual machine hot migration through vMotion". If you want to know more about it, you are welcome to follow the industry information channel. Thank you for reading!

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