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Native backup and size of target disk

I use the native backup system on my SBS 2011 Std server. I currently backup to a 2TB drive. I would like to use a higher capacity drive so that I can keep more backup sets than what I can currently store on the 2TB drive. I have a 6TB drive available (not currently being used for anything). Can the backup system properly use this size drive or does the windows 2TB limit come into play (i.e. will it fill the entire 6TB)?
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Dr. KlahnPrincipal Software Engineer

For operating systems after Windows XP, there is no 2TB limit on drives.  You can use as large a drive as you like ... though always bearing in mind that the bigger the drive, the more will be lost when it fails; and that all drives do eventually fail.  Keeping a single backup is good; keeping multiple copies is far better, because when the time comes that a backup is needed, you don't want to find that the host drive developed a bad spot right at the end of the 2TB backup file.
Adam BrownSenior Systems Admin
Top Expert 2010

As long as the new, larger drive is formatted as a GPT drive instead of an MBR drive, Windows should be able to use all the space. The 2TB limit is a "feature" of the MBR style partitioning system that most drives in SBS 2011's time period used. Modern drives use a GPT partitioning system that allows significantly more space. The limit isn't a limitation to Windows, so as long as the 6TB drive is created as a GPT partition, it'll work.


Thanks, I understand. The server will have a 1TB RAID1 drive that I plan on using as the boot drive and a separate 2TB drive that I plan on using as the data drive. Will these also need to be GPT formatted or can they be MBR's while the 6TB drive is GPT?
Distinguished Expert 2018
Okay.  This is more nuances that previous answers gave.  *WINDOWS* can access larger drives as answered.  But *BACKUPS* in 2008 R2 (and by proxy SBS 2011) use the older .vhd file format, which still has a 2TB limit.  Backup wasn't updated to use .vhdx until 2012.  So there are definitely conditions where a backup will not work with large drives.  

Additionally, many larger drives fall into either "enhanced" 512 sector drives where the drive does some remapping, or "native 4k" sector drives.  While drives larger than 2TB has been around since XP, Microsoft's native 4k wasn't fully baked until much later (2012 R2 is when I'd really say it was "stable" in the real world.)  And the remapped 512 drives are really vendor-specific as far as compatibility.  There are a lot of drives that still come out where price beats functionality...and it shows.  YMMV.