Increase SCSI tape drive performance
Many SCSI controllers have their default BIOS settings optimally configured for hard drives and other types of logical devices. However, tape drives are streaming devices and generally do not use the same settings as these other devices.
If configurable, disable the Synchronous Negotiation option for the entire SCSI host adapter or the particular device. Many modern SCSI host adapters have this configurable through the BIOS or via a jumper/switch setting. Also, if possible, set the bus transfer rate to the smallest allowable, working your way back up until the tape drive functions as expected. Many SCSI host adapters can be set to data transfer rates higher than most drives can accurately handle.
Initiate Sync Negotiation - No
Initiate Wide Negotiation - No*
Maximum Transfer Rate - 5 Mbytes/sec*
Enable Disconnection - Yes
Send start unit command - No
*If the tape drive is a Wide device, set Initiate Wide Negotiation to Yes and Maximum Transfer Rate to 20 Mbytes/sec.
About the author: Craig Konas is a senior member of NovaStor Corporation's Technical Support group. Craig has assisted thousands of customers with backup and disaster recovery during each of his 5 years with NovaStor. NovaStor technical support is a free service to customers.
This was first published in January 2002