Shulou(Shulou.com)05/31 Report--

Today, I would like to talk to you about how to conduct vmotion analysis, many people may not know much about it. In order to make you understand better, the editor has summarized the following contents for you. I hope you can get something according to this article.

1. Both vMotion and Storage vMotion need a dedicated VMkernel network to migrate virtual machines, so it is necessary to configure a dedicated network for vMotion on each ESXi host, and considering the performance problem, it is best to bind a dedicated Nic to the vMotion network. VMotion requires that the network bandwidth be at least gigabit and that the source and destination hosts have the same network configuration, including the network type and network label.

2. Check the network connection between servers. Migration depends on network connections, so any connection problems between the source / destination server can easily affect migration activity. The most direct method is the network connection between the ping source / destination server. If the ping is successful, prove that the lan communication between the source and destination servers is normal. If unsuccessful, the network cards (nic) on the source and destination servers may have connectivity problems or incompatibility. A common compatibility problem is the use of very long frames. For example, if one server's nic is configured to support very long frames and the other does not, the two servers will not communicate properly and the workload migration will not succeed unless the configuration of the two nic is exactly the same. Another common problem occurs when using the hostname ping of the target server. If the hostname ping fails, but the ip address ping is normal, it means that there is a problem with hostname resolution, and solving this problem will be helpful to solve the connection problem.

3. If a cluster uses an independent DVS distributed virtual machine switch, the virtual machines in the cluster will not be migrated to other clusters. The physical hosts in the cluster can be added to the distributed virtual switch under the overall larger vdc before the virtual machines in the cluster can be migrated to other clusters.

4. Traditionally, vmotion needs to consider the balance of computing resources between hosts and virtual machines. It is important to check the computing resources on the destination server, and if there are not enough computing resources on the destination server, the workload migration will fail. When the destination server lacks sufficient processing core, memory space, nic ports, or storage, it cannot reserve new workloads. With the decline in the number of physical servers and the increase in the level of workload consolidation, this has become a more and more common problem. For example, a shortage of resources occurs if the target server has failed to accept additional workloads from other systems. In addition, if the existing workload on the destination server has acquired additional computing resources to meet the more resource requirements caused by the increase in user activity, the resource shortage will also occur. Try to migrate the workload to another system with sufficient computing resources (such as idle or standby servers), or perform workload balancing on servers that need it.

5. If vmotion migration does not take into account the availability of the network, it sometimes leads to the placement or migration of virtual machines to hosts that are already saturated with the network. If the application happens to be network-sensitive, this may have some performance impact on the virtual machine.

6. During the vmotion migration, the virtual machine memory that is too large will migrate more slowly, because the dynamic synchronization of memory will take more time.

7. Pay attention to hardware compatibility when migrating vmotion. Check the compatibility and device dependency of the server hardware. Virtualized servers are designed to pull the underlying hardware away from the upper workload-- which makes workload migration possible-- but there are a small number of situations that may lead to hardware incompatibility between the source and destination servers, causing the migration to fail. The first step in troubleshooting is to evaluate the server hardware and configuration. To take a simple example, the source / destination server needs to use exactly the same processor for workload migration. Slightly different processing or iCompo virtualization settings for each system bios can also cause hardware problems. Migration also fails when vm relies on hardware that is not available on the destination server. For example, hypervisor such as vmware esx/esxi allows vm to connect to the physical disk. If vm relies on the physical disk connected to the source server-- which is not on the destination server-- the migration is problematic. Securely disconnect any local physical disks or client devices on the source server vm before re-migrating.

8. Due to the migration problems caused by different virtual machine versions, note that the high version cannot be migrated to the lower version.

9. Partition table format. This is a very serious problem. Many migration tools do not support system migration in GPT format, but only support system migration in MBR format. You need to pay special attention before choosing tools.

10. After migration, the disk cannot mount the partition of the original system successfully, and the system cannot be started successfully. When this happens, it is very likely that the original system is mounted using the device name, and the hard disk interface has changed in the two virtualized environments, for example, from the original IDE interface to the virtio interface, so that the device name will change, and the device name will change from the original sda to vda, which requires modification of the fstab (CD boot, enter emergency mode). Generally speaking, this problem does not occur if it is mounted through UUID.

After reading the above, do you have any further understanding of how to conduct vmotion analysis? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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