STATUS CODE: 86, 84, Backups are failing when using AIT-4 drives with Veritas NetBackup (tm) 6.0

Article:TECH45854  |  Created: 2006-01-06  |  Updated: 2009-01-28  |  Article URL http://www.symantec.com/docs/TECH45854
Article Type
Technical Solution


Environment

Issue



STATUS CODE: 86, 84, Backups are failing when using AIT-4 drives with Veritas NetBackup (tm) 6.0

Error



exit status 86: media position error
exit status 84: media writer error

Solution



Overview
Backups to various supported AIT-4 drives have been known to fail with a Status 86 (media position error) or Status 84 (media write error) when running NetBackup 6.0.  This is known to be caused due to a problem with detecting the Small Computer System Interface (SCSI) protocol supported by the drive.  If NetBackup detects that a drive will support the SCSI-3 protocol, it will execute additional commands using a 16-byte Command Descriptor Block (CDB).  If the drive does not support the SCSI-3 protocol, this will cause position and write failures during backup and restore operations.

This has been seen in an environment running Network Data Management Protocol (NDMP) backups using a Spectra Logic 10000/12000L robot with Sony SDX-900V drives.  Spectra Logic has confirmed that the latest 0103 AIT-4 firmware does not support SCSI-3.   This has also been seen with Sony AIT SDX-900V tape drives attached to a Windows 2003 server.  Refer to TechNote 278692, found below in the Related Documents section, for currently supported AIT-4 drives for use with NetBackup 6.0 and Technote 284599 for NetBackup 6.5.  

Troubleshooting
Check to determine if any of the tape drives on the media server are AIT-4 drives.  For AIT-3 drives which use SCSI-2 protocol NetBackup will not issue these 16-byte CDB commands.  Otherwise, enable logging for the bptm daemon on the media server to determine what errors are occurring during the backup.  Refer to the Related Documents section for information on how to enable logging.

Log Files  
The /usr/openv/netbackup/logs/bptm/log.<date> file may show the following errors:
<2> write_backup: block position check: actual 6271119, expected 6271117
<2> set_job_details: Done
<16> write_backup: FREEZING media id A00001, too many data blocks written, check tape/driver block size configuration

Resolution
Make sure the latest supported firmware is installed on the robot and drives to determine if the latest supported firmware fixes this issue.

When running NetBackup 6.x, the following workaround can be applied to disable the use of 16-byte CDB commands, by creating the following empty file:
<install_dir>\Volmgr\database\NO_SIXTEEN_BYTE_CDB
This will disable the use of 16-byte CDB commands. It will not be necessary to restart NetBackup for these changes to take effect.  The file will be read during the next backup or restore operation.

Supplemental Materials

SourceError Code
Value86
DescriptionNetBackup Error 86: media position error

SourceError Code
Value84
DescriptionNetBackup Error 84: media write error


Legacy ID



281312


Article URL http://www.symantec.com/docs/TECH45854


Terms of use for this information are found in Legal Notices