To view a device's configuration properties

1. On the navigation bar, click Devices.

2. Expand the server icon, click Stand-alone Drives, or if the drive is attached to a robotic library, click Robotic Libraries.

3. Select the device for which you want to view properties.

4. Under General Tasks in the task pane, select Properties, and then on the Drive Properties dialog box, click Configuration.

   The Configuration tab for drive properties provides the following information:

   Enable compression	If this option is available, this device is capable of supporting hardware compression. Select this check box to enable hardware compression. If a job is configured to use hardware compression, but is run on a device on which hardware compression is disabled (even though it is supported), hardware compression is considered unavailable and is not used. If a device that does not support hardware compression is added to a cascaded drive pool, the hardware compression option on all other drives in that pool is automatically disabled. You can enable the hardware compression option on the other drives again, but the pool will then have mixed compression, and could make restore operations difficult.
   Block size (per device)	The default is the preferred size of the blocks of data written to new media in this device. You can change the block size by selecting another size from the scroll list, and then clicking OK. Some devices (for example, DLT devices) provide better performance when larger block sizes are used. The preferred block size can range from 512 bytes to 64 kilobytes or larger. If you use a device that supports larger block sizes, you can change the device's block size in the Device Configuration tab. However, if the option to change the block size is unavailable, you must configure the device to use a larger size. See the device manufacturer's documentation for help in configuring the device. Backup Exec does not ensure that the requested block size is in fact supported by that device. You should check the device specifications to make sure that the block size is supported. If the device does not support a block size, it will default to its standard block size. If the device does not support block size configuration, this option is unavailable.
   Buffer size (per device)	The default is the preferred amount of data sent to the device on each read or write request. The buffer size must be an even multiple of the block size. You can change the buffer size by selecting another size from the scroll list, and then clicking OK. Depending on the amount of memory in your system, increasing this value may improve device performance. Each type of device requires a different buffer size to achieve maximum throughput.
   Buffer count	The default is the preferred number of buffers allocated for this device. You can change the buffer count by selecting another count from the scroll list, and then clicking OK. Depending on the amount of memory in your system, increasing this value may improve device performance. Each type of device requires a different number of buffers to achieve maximum throughput. If you change the buffer count, you may need to adjust the high water count accordingly.
   High water count	The default is the preferred number of buffers to be filled before data is first sent to the device, and any time after that if the device underruns. You can change the high water count by selecting another count from the scroll list, and then clicking OK. The high water count cannot exceed the buffer count. A value of 0 disables the use of high water logic; that is, each buffer is sent to the device as it is filled. The default setting provides satisfactory performance in most instances; in some configurations, throughput performance may be increased when other values are specified in this field. If you increase or decrease the buffer count, the high water count should be adjusted accordingly. If a device has a high water count default of 0, it should be left at 0.
   Default Settings	Click this button to return all the Preferred Configuration settings to their defaults, and then click OK.
   Read single block mode	Select this check box to have this device read only one block of data at a time. If this check box is selected, the device will read a single block of data at a time, regardless of the size of the buffer block. Symantec recommends selecting this option if the device is a shared storage device.
   Write single block mode	Select this check box to have this device write only one block of data at a time. Selecting this check box provides greater control over the handling of data write errors. Symantec recommends selecting this option if the device is a shared storage device.
   Read SCSI pass-through mode	Select this check box to have this device read data without going through a Microsoft tape device API. Selecting this check box allows the data to pass directly through the device and allows more detailed information if device errors occur. Symantec recommends selecting this option if the device is a shared storage device.
   Write SCSI pass-through mode	Select this check box to have this device write data without going through the Microsoft tape device API. Selecting this check box allows data to pass directly through the device driver and allows more detailed information if device errors occur. Symantec recommends selecting this option if the device is a shared storage device.