Dell PowerVault LTO3-060 - Manual (Page 9)

In some cases data will actually expand when subjected to both the hardware and software compression. This can
occur when sending data already compressed at the software application level to the drive and the compression
option is enabled. If this is the case the drive may try to turn compression on and off to optimize the data storage
having the negative unintended result of data expansion.
Note: The PowerVault LTO-2-024 has compression On by default. The compression can be turned Off by
using the SCSI Mode Select command.
2. Turn Off any software compression in use.
The compression is already being accomplished at the hardware level of the PowerVault LTO-2-024 drive.
Therefore any other compression software in the host or on the host bus adapter should be turned off.
The data is compressed using the SLDC (Streaming Lossless Data Compression) algorithm that is based on ALDC
(Adaptive Lossless Data Compression). The SLDC format is defined in the ECMA-321 standard. Two enhancements
are introduced:
o
Two methods to reduce expansion of uncompressible data.
o
Embedded code word.
Slow Performance
Check that the software driver used for the PowerVault LTO-2-024 is the latest version.
Check the SCSI ID
Each device on the SCSI bus needs a unique SCSI ID. The SCSI ID is set with jumpers on the back of the drive.
Check SCSI termination
The SCSI bus should be terminated at the end of the cable. A defective terminator may affect the drive.
Clean the tape drive.
Perform a Drive Diagnostics test.
Intermittent Failures
If the drive fails intermittently:
1. Clean the tape drive.
2. Check the SCSI termination on the SCSI bus.
3. Check the operating system logs for any errors.
If the problem occurs in the middle of an operation:
1. Use a different data cartridge.
2. If the error occurs when the software scans for the files to be backed up, please operate a SCANDISK (or similar)
operation to check the state of the File Systems(s) and hard disk.
If the error consistently occurs on the same file or directory:
1. Try to remove the file or directory from the backup operation to see if that corrects the problem.
2. Use a different data cartridge before the drive is sent for service.
3. If the issue is still not resolved, contact technical support.