Netbackup 7.1.0.3 Snapshot Client Block level incremental backups

[jmanini]

I am just starting my testing on moving all of my VM's off of Agent based backups to the Flashbackup based backups. My test machine does a full backup in about 45 minutes. I then did a test trying the Cumulative Incremental Backup which took about the same time. I saw that the Incrementals only backed up a few hundred files so that looks right but the time it took was crazy. What is the advantage of doing a block level Incremental? If our hundreds of servers took that long each night it would not be possible to fit them in. I did try a Cumulative backup with the Block level turned off and it only took a few minutes as expected. Is this the expected experience and if so  how can folks possibly do it.  Thank You

[VirtualED]

jmanini,

You should open a case for this one.  Here are my guess:

1.  If you run the Full Backups too close to the incremental backup (You have to wait over 1 hour), it assumes it is a Full Backup.

2.  Change Block Tracking(CBT) on the VMware side is findings many blocks on the VM are dirty thus BLIB is backing up more blocks than you expect to see.

3.  Both Full Backups and Incremental backups remove the white spaces from the VM.  So if the size of your Full and Incremental backups are similar is size (minus the file count).   You may have a problem with CBT on your VM. 

Limitations on Changed Block Tracking
Changed Block Tracking does not work in any of the following cases:
-Virtual hardware version is 6 or earlier.
-The virtual disk is a "physical compatibility RDM."
-The virtual disk is attached to a shared virtual SCSI bus.
Changed Block Tracking can be enabled on virtual machines that have disks like these, but when queried for their change ID, these disks always return an empty string. So if you have a virtual machine with a regular "O/S disk" and a pass-through RDM as a "data disk" you can track changes on the "O/S disk" only.