Backup Time and System Performance

When the Ntbackup.exe program uses buffered input/output (I/O) to write to a destination .bkf file, the cache manager and the memory manager in Microsoft Windows Server 2003 may handle a large volume of data at a high throughput rate. This process consumes valuable system resources and may affect system performance.

Resolution

1. Install either the hotfix mentioned here: http://support.microsoft.com/kb/839272 or SP1? for Windows 2003 to enable the use of the /FU command.

2. Now, add the following script to the pre-backup script section in BackupAssist (Advanced Tab > Modify scripts to run before and after the backup > pre-backup script):
   reg add "HKCU\Software\Microsoft\Ntbackup\Backup Engine" /v "Logical Disk Buffer Size" /t REG_SZ /d 64 /f

   reg add "HKCU\Software\Microsoft\Ntbackup\Backup Engine" /v "Max Buffer Size" /t REG_SZ /d 1024 /f

   reg add "HKCU\Software\Microsoft\Ntbackup\Backup Engine" /v "Max Num Tape Buffers" /t REG_SZ /d 16 /f

   
   Figure 1: Pre-Backup Script

   More details on this here: http://www.microsoft.com/technet/itsolutions/msit/operations/exchbkup.mspx

3. Now add the /FU command to the Advanced NTBackup Options in BackupAssist (Advanced Tab > Advanced NTBackup Options)
   
   Figure 2: Advanced NTBackup Command

4. Using the /FU command and the above registry commands on a Windows 2003 Server with SP1? reportedly gives a throughput to a network drive (1gb backbone) at about 1GB per minute (load depending of course), with local disks being up to 1.6GB per minute.
   Many thanks goes to Roland Schmid from Multiplex Limited, Australia for this advice.