The latest ARCserve release (r15) now supports incremental/differential backups of UNIX/Linux filesystems, so we made the jump.
As most of our Windows and Linux servers are now VMs running in our VMware cluster, we have opted to perform block level VM backups. To do this, we installed the ARCserve Backup Agent for Virtual Machines on our vCenter server.
ARCserve uses the VMware Virtual Disk Development Toolkit (VDDK) to provide integration with the VMware Data Protection APIs. I installed this on our vCenter server and configured the ARCserve server to backup all the VMs using the vCenter server as a proxy (note: this is not a VCB proxy as it does not copy the files, rather the VDDK provides a direct way of accessing the underlying VMDKs).
The problem we had was that the VM backups failed with the following error:
VMDKInit() : Initialization of VMDKIoLib failed
To cut a long story short, the problem was that the vCenter server is 64bit (required by vSphere 4.1). The fix, provided by CA support, was to extract the vddk64.zip file in C:\Program Files (x86)\VMware\VMware Virtual Disk Development Kit\bin.
The problem here appears to be that the VMware installer for the VDDK does not create the 64bit files when installing on a 64bit version of Windows. By adding these and restarting the ARCserve processes, the backup worked successfully.
Now to test the overnight backup of all our VMs...
Edit: The backup appears to be working fine!
Edit 2: Forgot to mention that the CA support representative also modified the system PATH variable to include the 64bit VDDK driver: C:\Program Files (x86)\VMware\VMware Virtual Disk Development Kit\bin\vddk64