Definition of terms within the various tabs of the Drive Properties dialog box

Article:TECH18486  |  Created: 2002-01-17  |  Updated: 2013-05-31  |  Article URL http://www.symantec.com/docs/TECH18486
Article Type
Technical Solution

Product(s)

Issue



Definition of terms within the various tabs of the Drive Properties dialog box


Solution



General tab

The General tab provides information about the drive (Figure 1).

Figure 1
 

Enable Device for Backup Exec - This check box must be selected in order for Backup Exec (tm) to use this device. Clear this check box to disable the device, and make the device available for other applications. If the check box is clear, the device is disabled, and it cannot be used by Backup Exec.

Pause Device - Select this check box to pause the device. To resume the device, clear this check box.

Online - If the device is online, the check box appears dimmed, with a check mark. If the device is offline, the check box is available, with no check mark. To bring the device online, check Online. No operations are allowed on the device until it is online again.

Name - The name of the drive. The device can be renamed by entering a new name in this field and then clicking OK.

Vendor - The name of the vendor of the drive.

Product ID - The product ID from the SCSI Inquiry string.

Firmware Version - The version of the firmware used in the device.

Drive Type - The media and memory specifications of the device.

Date in Service - The date this device was first detected by this installation of Backup Exec (tm).

Cartridge Type -  The type of media used by this device.

Full Name - Displays the drive name and server name.

Serial No -  The serial number of the drive.


Configuration tab

The Configuration tab (Figure 2) allows the following:

1. Enabling or disabling hardware compression (if compression is supported by the drive)
2. Changing the preferred block size, buffer size, buffer count, and high water count


Figure 2
 

Caution: Preferred configuration settings are used to tune the performance of backup and restore operations. Changing Preferred configuration settings is not generally recommended and may have a negative effect on your backup and system performance. Any changes should be thoroughly tested to make sure that the system performance does not deteriorate before being put to general use.

Enable Hardware Compression - This option will only be available if the 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 drive on which hardware compression is disabled (even though it is supported), hardware compression is considered unavailable and is not used. If a drive that does not support hardware compression is added to a cascaded drives pool, the hardware compression option on all other drives in that pool is automatically disabled. The hardware compression option on the other drives can be enabled again, but the pool will then have mixed compression, and could make restore operations difficult.

Priority - The Priority field is only available when the drive belongs to a drive pool and is selected for viewing, under the drive pool icon. Drive properties displayed under the robotic libraries or stand-alone drives icon do not display the Priority field. Set a priority for a drive that determines the order in which the drives in a drive pool are used. In the Priority box, type a number between 1 to 99, with 1 designating this drive as the first drive to be used in the drive pool, or click the arrows to select a value. The default priority is 10, so all drives have the same priority initially. The drive to which you assign the lowest number is the first drive to be used in the drive pool. For example, a drive with a priority of 1 is used before a drive with a priority of 5.

Preferred configuration -  Preferred configuration settings are used to tune the performance of backup and restore operations.

Note: Changing Preferred Configuration settings is not generally recommended and may have a negative effect on your backup and system performance.  Any changes should be thoroughly tested to make sure system performance does not deteriorate before being put into general use.

Block Size (per device) - The default is the preferred size of the blocks of data written to new media in this device. The block size can be changed by selecting another size from the drop-down list box, and then clicking OK. Backup Exec does not ensure that the requested block size is in supported by that drive. Check the drive specifications to make sure that the block size is supported. If the drive does not support a block size, it will take its standard block size as the default value. If the drive does not support block size configuration, this option will not be available.

Buffer Size (per device) - The default is the preferred amount of data sent to the drive on each read or write request. The buffer size must be an even multiple of the block size. The buffer size can be changed by selecting another size from the drop-down list box, and then clicking OK. Depending on the amount of memory in your system, increasing this value may improve drive performance. Each type of drive requires a different buffer size to achieve maximum throughput.

Buffer Count - The default is the preferred number of buffers allocated for this device. The buffer count can be changed by selecting another count from the drop-down list box. Depending on the amount of memory in your system, increasing this value may improve drive performance. Each type of drive requires different number of buffers to achieve maximum throughput. If the buffer count is changed, the high water count needs to be adjusted accordingly.

High Water Count - The default is the preferred number of buffers to be filled before data is first sent to the drive, and any time after that if the drive under runs. The high water count can be changed by selecting another count from the drop-down list box. 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 drive as it is filled. If a drive has a high water count default of 0, it should be left at 0. Increasing the high water count may increase performance in older drives and decrease it on newer ones.

Default Settings - Click this button to return all the Preferred configuration settings to their default values.


SCSI Information tab

The SCSI Information tab provides information about the drive (Figure 3).

Figure 3
 

Inquiry - The device information read from the device firmware.

Port - The identifying number of the port on the server to which the device is attached.

Bus - The identifying number of the bus to which the device is attached.

Target ID - The unique SCSI ID number (physical unit number).

LUN - The logical unit number of the device.


Statistics tab

The Statistics tab provides the date the drive was last mounted, drive totals such as the total number of bytes written and read, and drive errors (Figure 4). Error rates are affected by media, head cleaning, and head wear. The documentation included with the device should list the acceptable limits for hard and soft errors; if not, check with the hardware manufacturer.

Figure 4
 

Last Mount Date - Last date when media was mounted by this device.

Bytes Written - Number of bytes that have been written by this device.

Bytes Read - Number of bytes that have been read by this device.

Total Mounts - Number of times that media has been mounted by this device.

Total Seeks - The total number of seek operations (performed when a specific piece of information is being located) that have been performed by this device.

Hours in Use - The total number of hours that this drive has been in use (performing read, write, mount, and seek operations).

Seek Errors - The number of errors encountered while trying to locate data.

Soft Read Errors - The number of recoverable read errors encountered. If soft read errors are received, it may indicate the beginning of a problem. If you receive excessive errors for your environment, check the device and perform maintenance on it. Check the media for damage.

Hard Read Errors - The number of unrecoverable read errors encountered. If hard read errors are received, check the device and perform maintenance on it. Check the media for damage.

Soft Write Errors - The number of recoverable write errors encountered. If soft write errors are received, it may indicate the beginning of a problem. If you receive excessive errors for your environment, check the device and perform maintenance on it. Check the media for damage.

Hard Write Errors - The number of unrecoverable write errors encountered. If hard write errors are received, check the device and perform maintenance on it. Check the media for damage.


Cleaning tab

The Cleaning tab provides statistics on totals and errors since the last cleaning (Figure 5). The documentation included with your device should list the acceptable limits for hard and soft errors; if not, check with the hardware manufacturer.

Figure 5
 

Last Cleaning Date - The last time when a cleaning operation was performed on the drive.

Hours Since Last Cleaning - The number of hours that the drive has been in use since the last cleaning.

Reset Cleaning Statistics - Click this button to reset all cleaning statistics to zero (stand-alone drives only).

Bytes Written - Number of bytes that have been written by this device since the last cleaning.

Bytes Read - Number of bytes that have been read by this device since the last cleaning.

Total Mounts - Number of times that media has been mounted by this device since the last cleaning.

Total Seeks - The total number of seek operations (performed when a specific piece of information is being located) that have been
performed by this device since the last cleaning.

Hours in Use - The total number of hours that this drive has been in use (performing read, write, mount, and seek operations) since the last cleaning.

Seek Errors - The number of errors encountered since the last cleaning while trying to locate data.

Soft Read Errors - The number of recoverable read errors encountered since the last cleaning. If soft read errors are received, it may indicate the beginning of a problem. If excessive errors for your environment are received, check the device and perform maintenance on it. Check the media for damage.

Hard Read Errors - The number of unrecoverable read errors encountered since the last cleaning. If hard errors are received, check the device and perform maintenance on it. Check the media for damage.

Soft Write Errors - The number of recoverable write errors encountered since the last cleaning. If soft errors are received, it may indicate the beginning of a problem. If excessive soft errors for your environment are received, check the device and perform maintenance on it. Check the media for damage.

Hard Write Errors - The number of unrecoverable write errors encountered since the last cleaning. If hard errors are received, check the device and perform maintenance on it. Check the media for damage.

Media Types Tab

Figure 6
 


Use the Media Types tab of a device's Properties dialog box to view media types that can be placed in the device and to specify whether these media types can be used for read or write operations.

The ADAMM database in Backup Exec maintains a list of media types, such as 4MM, and then further defines the sub categories or specifics of a media type. For example, a 4MM media type can include 4MM DDS-1 with a length of 60m and the storage capacity of 1.3 GB. Another 4MM tape might also be a 4MM DDS-1 but have a length of 90m and a storage capacity of 2.0 GB.

By default, the Media Types tab for a device lists all known media type categories and allows all media types to be used for both read and write operations. If a number appears in brackets beside the media type, that media entry is available for use when creating a bar code rule. You can specify that the device be limited to performing read and write operations on specific media types. For example, if your device's documentation states that the device cannot perform write operations to a 4MM DDS-4 tape, you can select that media type from this dialog box, clear the Write check box, and then click OK. This information is then incorporated in the ADAMM database, allowing Backup Exec to exclude this media type when searching for media to be used for an operation (such as a backup job) requiring the writing of data to the media.

Media type options for a device  

Media Type  Type of media, such as 4mm, and any defined category of this media type, such as CLN for cleaning tape. Media types that have numbers appearing in brackets (for example, 4mm [6]) can be used to define specific bar code rules.

Read  Displays Yes if this media type can be read by the device; otherwise, displays No

Write  Displays Yes if this media type can be written to by the device; otherwise, displays No



Legacy ID



244747


Article URL http://www.symantec.com/docs/TECH18486


Terms of use for this information are found in Legal Notices