DLT VS80 very slow when doing verify

[BR734811]

Hello everybody,

I have a problem with a VS80 external DLT drive using NTBACKUP (W2K server) for dayly tape backups.

The speed for writing the backup save set is ok., but when the software starts the verify pass it slows down by a factor of maybe 20. The backup of a 750 MB save set lasts for example 10 Minutes, the following verify lasts nearly 3 hours.

I know, that NTBACKUP is not the ideal software (for it uses a too small block size), but I have another server with another DLT of the same type, where it works fine with NTBACKUP, so this seems to be ruled out as an explanation.

Thanks in advance, if anyone can give me a hint!

Uwe

[CA923306]

Hello Uwe,
Couple suggestions that may help you with your issue.

1. Disable Verify. These drives have a read after write function that automatically verifies the information written to the tape after each pass by a read/write head. (there are multiple heads). Verify simply checks that the same size of data was written as the size of data that was sent down.

2. In your scsi cards BIOS increase the sync transfer rate for the scsi id associated with your tape drive.

3. Consult the Microsoft Knowledge Base for information on where Block Size can be modified and change this to at least 64k. (65536 bytes). Sometimes this setting resides in an .ini file or within the software itself.


Thank you for your inquiry. I Hope this helps,

Tom Cuttriss