Virtual Disk API Programming Guide - Documentation - VMware

Virtual Disk Programming Guide
When performing a proxy backup of an RDM disk, you must present the same LUN ID to both the ESXi host
and the proxy server. (This restriction does not apply to VMFS disk because the virtual disk library reads the
VMFS header and matching UUID. But for RDM the host and proxy require the same LUN ID.)
Restoring RDM disks is appropriate if the original virtual machine’s VMX file and disk mapping is no longer
available, but the LUN containing the RDM is still available. In this case, the RDM image on the LUN might
still be valid, so it does not need to be restored. If this is true, do not make changes to the RDM configuration
during your restore operations. Instead, complete the restore process in two phases:
Restore the virtual machine configuration (VMX) and system disk. This restores the virtual machine, but
does not restore the RDM.
Add the RDM disk to the virtual machine. After doing so, you can complete normal restore operations on
the RDM disk.
Alternatively, it is possible to create a virtual machine that can host the RDM disk and access its contents. After
you create the virtual machine, restore its virtual machine configuration (VMX) from backup, and then restore
any selected disks.
Restoring the Virtual BIOS or UEFI
The .nvram file stores the BIOS or UEFI customizations of a virtual machine. Usually the only important items
in this file are the boot drive setting and the boot order (in the case of multiple virtual disks).
Newer releases of vSphere can change the boot order using extended attribute settings, so boot order no longer
must be stored in the .nvram file. However some users want to preserve a virtual machine’s serial port settings
in the .nvram file, and possibly other items, so applications should back up and restore this information.
To back up and restore NVRAM
1 For each virtual machine, make a separate copy of the .nvram file.
2 Back up each virtual machine using standard methods.
3 If necessary, restore the virtual machine using standard methods.
4 Overwrite the virtual machine’s .nvram file with the saved copy of the original .nvram file.
IMPORTANT VMware now recommends saving the .nvram file as part of virtual machine backup, a change
in recommendation since vSphere 4.1.
Interfacing With VMware vSphere
This section provides pointers to other vSphere programming interfaces.
The VIX API
The VIX API is a popular, easy‐to‐use developer interface for VMware Workstation, other hosted products,
and ESX/ESXi. See the VMware developer documentation for information about the VIX API:
http://www.vmware.com/support/developer/vix‐api
The VIX API Reference guide includes function reference pages for C++, Perl, and COM (component object
model) for Microsoft C#, VBScript, and Visual Basic. Most reference pages include helpful code examples.
Additionally, the vix‐api Web guide includes examples for power on and off, suspending a virtual machine,
taking a snapshot, guest operations, virtual machine discovery, and asynchronous callbacks.
Virus Scan all Hosted Disk
Suppose you want to run the antivirus software presented in “Scan VMDK for Virus Signatures” on page 49
for all virtual machines hosted on a VMware Workstation. Here is the high‐level algorithm for an VIX‐based
application that would scan hosted disk on all virtual machines.
54 VMware, Inc.