VMware plugin v1.0 fails to backup large images (4045630)

Date - Jan 2009
Affected Product & Version - NetVault: Backup 8.x
Affected Module & Version - Vmware plugin v1.0
OS Version - ANY
Application Information - N/A


Symptoms:
Vmware 'Image-Level' backups fail when the backed up image is large.
The failure to backup has been reported for images ranging from 250GB to 1TB in size.
This problem has been reported for both VCB Proxy backups as well as 'local' backups via the COS.

The NetVault log shows the following messages:
Information 2009/01/22 01:06:37 73 Data Plugin BCKP-VCB Starting Program 'C:\Program Files\VMware\VMware Consolidated Backup Framework\vcbMounter.exe'
Information 2009/01/22 01:06:45 73 Data Plugin BCKP-VCB Deleted directory F:\mnt\w2k3
Job Message 2009/01/22 01:06:46 73 Data Plugin BCKP-VCB Finished with exit code 0
Error 2009/01/22 01:06:46 73 Data Plugin BCKP-VCB Failed to backup VM w2k3
Error 2009/01/22 01:06:46 73 Data Plugin BCKP-VCB Error writing to backup media


Reason:
From the NetVault trace, it appears the Vmware plugin has difficulties opening the large '.vmdk' file.
The following events occur before the failure:
- the job starts with a media request and allocates a tape
- the plugin triggers the vcbmounter scripts
- vcbMounter quiesces the image, takes a snapshot of it and mounts it to the defined temporary directory for backup
- at this moment the Vmware plugin issues another media request, cancelling the first one
- the transfer to tape starts
- when it is time to backup the '.vmdk' image file itself, the plugin fails to open the file for backup, the following trace message is returned:

1 VMWBCKUP:1664 18 0 090948 Writing entry 'scsi0-0-0-w2k3.vmdk', headersize '66', filesize '327680'
4 OBJECT :1664 179 0 090948 ObjSerializeToMemorySized(0x8498e98, 0x8497bfb, 66)
0 VMWBCKUP:1664 19 0 090948 Failed to update media stream
0 VMWBCKUP:1664