From Michael Kleef’s blog:

Yep its true. NTBackup is gone….at least as you know it! You can have it back again with a download but its only so that you can read data from tapes or media you already have that you created previously. Its been replaced with Windows Server backup. This does pretty much what the old one did with one omission….it no longer supports tape units.  Personally when I was an IT Pro working for a systems integrator – I hated tape units. They were an absolute pain in the neck and generally unreliable. That said we still do implement the tape drivers in the OS, just not the tape support in Windows Server backup. Instead we now support optical media and support hard disk based backup. Some people actually liked tape though and even used Ntbackup to perform their daily backups- though in the vast majority of cases these were very small business customers.

Though here’s some of the rationale why it makes sense:

1. The vast majority of customers, especially those with large data backup sizes above what small business typically backs up, used third party backup tools like Veritas Backup Exec or Commvault. It makes sense – these tools gave significantly better functionality and granularity than what we provided. These third party tools still support tape units in Windows Server 2008 even though we don’t.

2. Ntbackup was never designed as an enterprise backup tool. I remember the days when ARCserve and Backup Exec started doing brick level backup of Exchange….and Ntbackup just couldnt…

3. Trends toward Optical and Disk backup are increasing and while people are still reliant on tape – many would rather not be. For small business optical and disk based backup suits quite well. Disk is relatively cheap, easier to maintain and store – especially removable disks – and with very high capacities! Backup and restore windows are quite a bit faster too.

If you have needs beyond the scope of Windows Server backup – use the third party tools. In many cases these companies have worked directly with us to make sure their product works well with any new advancements we made in file systems or snapshot support. Ours is intended to be an entry level product. Dont assume it will do more than that.

Source: NTBackup is gone from Windows Server 2008