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Title
NDMP backups to VTL that duplicate to tape do not restore -
Description
Title: NDMP backups to VTL that duplicate to tape do not restore
Date: 12-Oct-2006
NV Version: all
OS Version: all
Application version:
Plugin version:
NDMP Plugin Module 6.304
Description: Problems restoring NDMP backups from duplicates on tape.
Symptoms:
NDMP backups made to VTL and subsequently duplicated to tape do not restore from the physical tape.
Backups made directly to tape and duplicated or datacopied to VTL restore correctly.
Example of errors seen in the bin logs:
Background 2006/09/26 08:20:00 648 Media bacser Mover has paused due to seek outside the supplied window
Error 2006/09/26 08:20:00 648 Media bacser Unexpected Pause Seek to a position in the current segment
Error 2006/09/26 08:20:00 648 Media bacser bacser 1-0.4.0 (HP Ultrium 3-SCSI): had channel error
This is caused by a difference in the block size on the VTL and physical tape.
If the block size of the VTL is different to the tape drive the restores fail.
If the block size is the same the restores work correctly.
This problem has also been observed with the NDMP daemon contained in the netware.nlm on NetWare systems, and with drdaemon for VaultOS restores. -
Cause
This is caused by a difference in the block size on the VTL and physical tape.
If the block size of the VTL is different to the tape drive the restores fail.
If the block size is the same the restores work correctly.This problem has also been observed with the NDMP daemon contained in the netware.nlm on NetWare systems, and with drdaemon for VaultOS restores.
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Resolution
Make sure VTL and tape device used for duplication have the same block size.
To change block size right click the drive and select config the select the configuration tab. It is advised that all media will need to be blanked before use on the device that has had the block size changed.
Note: You may need to experiment with different block sizes to get the best transfer speeds for your configuration.
If you already have backups that have duplicated to tapes with a different block size, you should be able to modify your block size for your drives, write a new tape header to a fresh tape, and then duplicate from the old tapes to that new tape written with the correct block size. You should then be able to restore from it.
Fault report opened NCG-173 -
Additional Information
BakBone SFDC Solution Number: 00001539