VMware has been able to resonate globally by providing users with virtualization solutions for desktops, servers, data, etc., while saving on IT expenses and simplifying management. Recently, a user in the use of the process of raising several questions, ‘seamless migration of virtual machines’ can be achieved will be virtualized between servers or storage arrays at will, and there is no impact on its performance, but has what attention to the matter is not clear, today to share knowledge in this regard.
1. Check whether the server migration settings are turned on
Before performing a VMware migration between servers first require both servers to have migration enabled. For example, vMotion must be enabled on both servers using VMware ESX or ESXi. if it is a Hyper-V server for VM migration, make sure that the dynamic migration feature is available on both servers. on VMware ESX or ESXi servers, vMotion is enabled on the Configuration tab for a specific vSphere client, so the IT administrators must use documentation that matches each hypervisor and enable the migration feature on each server.
2. Check server hardware compatibility and device relevance
Virtualized servers are specifically designed to abstract the underlying hardware away from the workloads on the top? The extraction makes workload migration possible? However, there are a small number of scenarios that may lead to hardware incompatibility between the source and destination servers, resulting in migration failure.
The first step in troubleshooting is to evaluate the server hardware and configuration. As a simple example, the source/destination servers need to use exactly the same processors for workload migration. Slightly different processing or I/O virtualization settings in each system’s BIOS can also cause hardware issues.
Migration can also fail when VMware relies on hardware that is not available on the destination server. For example, hypervisors like VMware ESX/ESXi allow VMs to connect to physical disks. If the VM relies on a physical disk that is connected to the source server ??? and there is no ??????? on the destination server. migration goes wrong. Safely disconnect any local physical disks or client devices on the source server VMs and then redo the migration.
3. Is the network connection between the servers working?
Migration relies on network connectivity, so any connectivity issues between source/destination servers can easily affect migration activity. The most straightforward method is to ping the network connection between the source/destination servers. For example, VMware’s vmkping can be used on the source server to ping the destination server using the command shell. Go to the host name or IP address of the destination server and view the successful ping feedback, e.g., vmkping 192.168.1.1
You can also perform this procedure using the standard ping command from a Windows command prompt or from the Linux command line. If the ping is successful, it proves that the LAN communication between the source and destination servers is normal. If it is unsuccessful, there may be an incompatibility between the network cards (NICs) on the source and destination servers.
A common compatibility issue is the use of ultra-long frames. For example, if one server’s NIC is configured to support ultra-long frames and the other is not, the two servers will not communicate properly and workload migration will not succeed unless both NICs are configured identically. Another common problem occurs when using a 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 the hostname resolution, and solving this problem will help to solve the connection problem.
4. Whether there are enough computing resources on the destination server
If there are not enough computing resources on the destination server, workload migration will also fail. When the destination server lacks sufficient processing cores, memory space, NIC ports, or storage, it cannot reserve new workloads. This has become an increasingly common problem as the number of physical servers declines and the level of workload consolidation increases.
For example, if the destination server has already failed from receiving additional workloads from other systems, a resource shortage can occur. Also, if workloads already on the destination server have been given additional computing resources to meet the increased resource demands caused by increased user activity, resource shortages can occur in this case. Try migrating the workload to another system with sufficient computing resources (such as an idle or spare server) or perform workload balancing on the server in need.
A common problem is a lack of disk space on the destination server, so check for available disk space. For example, a VMware ESX/ESXi user can open a console toward the destination server and use the df -h command to monitor easy-to-use space (or use the vdf ?h command to check space on a VMFS volume). If there is not enough space to store the migrated workloads, the administrator needs to either free up space or migrate the workloads to another system. If storage is provided over a storage area network (SAN), confirm that the source and destination servers are configured with the same partitions.
Migrating virtual machines between servers as one of the basic functions of VMware virtualization, although the operation method is simple, but if any one of the settings is not correct or configuration problems, it will lead to migration failure, so before implementing the relevant functions, it is important to master the method, so that you can be prepared.