How do VMware snapshots work

The best tips and tricks for VMware vSphere and ESXi

Correctly insert and delete snapshots

If you take frequent snapshots in VMware environments, there is a possibility that the VMs will suffer from performance degradation. The older Snapshot is, the bigger it gets. Make sure you adhere to the recommended parameters and delete snapshots that are older than 72 hours. Snapshots are not a permanent and reliable data backup, but are only intended to secure configuration changes.

The best way to take proper snapshots is to stop, pause, or shut down a virtual machine before taking the snapshot. Slow snapshots often occur when VMs run out of resources. In general, it makes sense to save the operating system on a different hard disk image than the data files of the virtual machine. The snapshot is then completed more quickly and the operating system is available while the snapshot is still being carried out on the data part.

Free monitoring

In addition to the well-known Veeam One tool, you can also use SolarWinds Free VM Monitor to monitor VMware for free. Incidentally, in addition to VMware support, Solarwinds also offers a version for Hyper-V.

Use VMware vShere Distributed Switches (VDS)

Standard switches are no longer up-to-date when using VMware. It is better if you use distributed switches. VMware vSphere Distributed Switches (VDS) offer more flexibility. A standard vSwitch can only work with one physical host, a vDS with different hosts in the same cluster.

Several network cards are necessary to be able to migrate to a VMware vDS. To do this, remove the network cards from the standard switch and connect them to the vDS. After all cards are connected to the vDS, you can remove the standard switch.

To manage the tasks, click with the right mouse button on the data center object. You can use the vSphere Web Client or the Windows Client. After creating the switch, right click on the object and select the option to add and manage hosts. This option allows you to add your vSphere hosts to the new vSD.

You can display and manage the port groups of your switches in the overview. It is best to migrate the virtual machines to vDS first and the VMkernel ports first. You can use the network migration wizard to do this. To do this, right-click the virtual distributed switch and select the wizard to move virtual servers to the new switch.

VMware: Commands for the console

In the service console, you can perform administrative tasks by entering various commands. The most important command for this is service. With this you can start, stop and pause various system components in VMware. The most important in this area are mgmt-vmware, vmware-vpxa, firewall, vmware-hostd and vmware Web Access.

Ps and kill can kill VMs that are unresponsive. Ps indicates the status. The EF option shows information about processes. The kill command ends processes again. For example, if you discover connection problems between the VMware environment and vCenter or other clients, some services can cause problems. You can exit this relatively easily and then restart it:

Then restart the services with:

Vmkping is a special VMware variant of ping. It uses parts of the VMkernel to ping the VMkernel port of other ESX hosts. vmkfstools can control virtual drives, in particular adjust the size of virtual drives or convert them. Esxtop displays statistics on CPU, memory, and disk usage. In a separate blog post, the developers go into further options for controlling VMware in the console.

Rename VMware files

If you use a large number of virtual servers in your company, you should make sure that the system files of the VMs are assigned directly to the corresponding VM and that they have their names. You can rename VMDK files at any time in VMware vSphere Hypervisor. If the name is correct, you can always see in the user interface which file corresponds to which drive in the individual VMs. To rename files, do the following:

1. Shut down the VM.

2. Remove the VMDK file in the properties of the virtual machine.

3. Open the shell.

4. Change to the directory of the VMDK file: cd / vmfs / volumes / /

5. Rename the files with vmkfstools -E "" "".

6. Reconnect the file to the VM and start the VM.

The other files will gradually be given a suitable name. You don't have to rename them.