Changing the preferred block size, buffer size, buffer count, and high water count for devices
Use the preferred configuration settings for a device to tune the performance of backup and restore operations. Changing preferred configuration settings is not generally recommended and may have a negative effect on backup performance and system performance. Thoroughly test any changes before you put them into general use to ensure that system performance does not deteriorate.
To change the preferred block size, buffer size, buffer count, and high water count for devices
On the navigation bar, click Devices.
Expand the server icon.
Select the device for which you want to view properties.
Under General Tasks in the task pane, select Properties, and then on the Drive Properties dialog box, click Configuration.
Click the drop-down menu for the item that you want to change, and then select a new setting.