Windows – Server Backup reports incomplete backup [0x80070020] due to item in System Volume Information Folder

The full is "leading". You're think of the week starting on a Monday. In the backup's "mind", the week starts on Friday or Saturday. Your weekly sets would be all the tapes from the full through the last incremental or differential before the next full. Don't think about "calendar weeks", think about "backup weeks".

It doesn't matter which day of the week you run the full on-- you'll still start a restore by bringing back the last full and then the last differential (or all incrementals) taken after that full.

Typically, Friday or Saturday is chosen to give the longest window of non-business hours time to take the full backup. If you have a better day of the week for the full, use it.

BTW: If you can get away with differential backups use them instead of incrementals. You have much less risk exposure.

Edit: An incremental backup contains only the changes since the last full OR incremental. A differential backup contains all the changes since the last full. Assuming you're piling a week's worth of incrementals or differentials on the same tape cartridge, they're functionally very close to equivalent.

If, however, you're using a different tape cartridge each day for the incremental, you have a dependence on each of those cartridges holding the incremental backups to work for a successful restore. With a differential backup scenario using a different cartridge each day, only the last full and differential cartridges are needed for a restore.

My wbadmin backup is also 10Gig on Windows 2008 64 bit. Tom's list short a few things i.e. the .NET framework files (on 64 bit also the 32 bit .NET FW files, which helps getting to 10G) and task scheduler files. This MSDN link (and this one) may help. Note also that some new Win 2008 based Domain Controllers will run DFSR instead of FRS, so it needs to be considered in the equation also.

Wbadmin makes use of the Volume Shadow Copy Service (VSS) to do the system state backup. It basically takes a VSS snapshot and gathers all the files together in a VHD file. There will be backup solutions out there that offer VSS based system state backups that will do the same as wbadmin but give incremental functionality and even Single instance storage e.g. Attix5. Most of the system state files really does not change very often like all the driver files, so you should get a huge drop in backup size after a full backup was done initially.

If you feel strong you can probably look into a tool that can extract files from VHD files or mount VHD files as windows drives and the use some backup tool to backup the exposed files.