最後更新: 2022-12-19

vswp

Memory overcommitment

 * memory from idle virtual machines is transfered to virtual machines that need more memory.

 * memory compression is enabled by default on ESXi hosts
    in order to improve virtual machine performance when memory is overcommitted.

 * memory overhead is stored in a swap file (.vswp) on the datastore.

.vswp file

This file is required by VMkernel to swap virtual machine memory to the disk in case of excessive overprovisioning.

.vswp size = Allocated Memory – Memory Reservation (default: 0)

How to disable swap files in ESXi?

Linux VMs on ESXi that contain very sensitive encrypted data that eventually get decrypted as required in memory.

Everything is fine, except for the ESXi swap files which could potentially store some of the decrypted data

Tab: Roursces -> Memory -> tick "Reserve all guest memory"

vmname-[8 character hexadecimal number].vswp

When the virtual machine requires more memory to be allocated,

the swap file will be used instead of physical memory even if its RAM setting is not overcommitted.

vmx-<vmname>-xxxxxx.vswp

This is a new file in ESXi 5 and is used by the vmkernel Memory Overhead that exist for each VM - in addition to the actual vRAM configured for the VM to use. This files holds some backing space needed for the Memory Overhead and reduces the amount of actual allocated extra RAM needed for each started virtual machine.

Virtual machine executable (VMX) swap files allow the host to greatly reduce the amount of overhead memory reserved for the VMX process.

VMX swap files are not related to the swap to host cache feature or to regular host-level swap files.

ESXi reserves memory per virtual machine for a variety of purposes. Memory for the needs of certain components, such as the virtual machine monitor (VMM) and virtual devices, is fully reserved when a virtual machine is powered on. However, some of the overhead memory that is reserved for the VMX process can be swapped. The VMX swap feature reduces the VMX memory reservation significantly (for example, from about 50MB or more per virtual machine to about 10MB per virtual machine). This allows the remaining memory to be swapped out when host memory is overcommitted, reducing overhead memory reservation for each virtual machine.

vmss

which stores the state of a suspended virtual machine

 * Make sure you got no snapshots that may depend on it - then you can delete it

如果有 VM 是 suspend 了, 而你 Delete 左 .vmss, 那相當於 "強制關機"
 

vmx

virtual machine setting

vmxf

virtual machines that are in a team
 

nvram

stores the state of the virtual machine's BIOS.