Maybe this can help you, it is rather complex but is works fine for us!
We have contacted VMware about this issue. VCB itself does not have a possibility to solve this problem. We have created a work-arround.
If you create a snapshot of a VM the VMDK files of the VM are set in read-only mode. This means that you can use the vmkfstools command to clone the VMDK file you wish to backup to a temporary location.
This is the setup of EMC Networker (our backup software).
You have to install your backup software on a ESX Server. Create a pre-backup script on the ESX machine which creates a snapshot of the VM you want to backup. The second command in this pre-backup script is the vmkfstools -i (use this to clone the VMDK file to a temporary location), the third command is to delete the snapshot). Then let your backup software backup the temporary file. In the post-backup script you can delete the temporary file. This means that the temporay location you use to clone the VMDK file to does not have to be very large. You can run one backup after another....
There is one problem we have encountered. The pre-backup script is executed at the ESX Host. Because we have multiple ESX Servers that are controlled by a VC Server we do not know which ESX Server contains the VM (because of DRS, VMotion). To create the snapshot we have to let VC execute the "Create Snapshot" command. You cannot execute this command from an ESX Host (From version 3.0.x the vmware-cmd command cannot communicate to a VC Server anymore, as far as I know)
To solve this problem we created a VM (WinXP) with VMware VI Perl Tooklit installed (you can download it at the download section). With this tool you can execute a command at the VC Server (from the WinXP machine). You can also install the Perl Toolkit at the VC Server itself.
All you have to do now is to execute a Windows batch file from the pre-backup script (which is execute from the ESX Host). This is the content of a batch file we used.
perl "C:\Program Files\VMware\VMware VI Perl Toolkit\Perl\apps\vm\snapshotmanager.pl" --server virtualcenter --username DOMAIN\User --password Password --operation create --snapshotname "Backup" --vmname "Name of VM"
You can execute a Windows batch file from a LINUX Host using the "winexe" command. This is a freeware tool you can find and download on the internet.
This is the content of a prebackup script we used:
/tmp/winexe -U 'DOMAIN\User%Password' //nameofthemachinewhereVIPerlisinstalled "cmd /C C:\Scripts\createsnapshot.bat" CREATE SNAPSHOT
/usr/sbin/vmkfstools -i /vmfs/volumes/p_vmconfig/Productie\ XP\ Heide/p_heide.vmdk /vmfs/volumes/local/p_heide.vmdk -d thin CLONE VMDK FILE
/tmp/winexe -U 'DOMAIN\User%Password' //nameofthemachinewhereVIPerlisinstalled "cmd /C C:\Scripts\removesnapshot.bat" DELETE SNAPSHOT
This is the post-backup script:
rm -f /vmfs/volumes/local/p_heide.vmdk
rm -f /vmfs/volumes/local/p_heide-flat.vmdk
If you have any questions please ask....
Joost.
