[Info-vax] Getting tape drive errors make no sense

[Darren Clark]

Also, double check your SCSI termination. Improperly terminated SCSI 
connections can cause parity errors.




On 10/25/2013 3:33 PM, tadamsmar wrote:
> I tried to copy a large save-set (a full disk backup) from tape to a large disk.  That is I am just trying to copy the file from tape to disk, not trying to restore a volume.
>
> The save-set was created and verified on a DDS3 tape on a DDS3 drive. One of those 12/24 GB DAT drives that are common on Alpha DS10 466 mhz systems.
>
> I was trying to copy it using a DDS4 hotswap drive on a Alpha DS10 617 mhz system.
>
> Both systems have disk shadow sets with 2 members.
>
> I got errors when I tried to copy.
>
> I did a search of the file and also got parity errors.
>
> I tested the tape on a 3rd system with a DDS3 drive (similar system that wrote the tape).  I could search it there with no errors.
>
> (I was using searching instead of copying as a test case because the 3rd system did not have big disks that would allow copying the whole file.)
>
> The DDS4 drive is backward compatible to DDS3. I does incrementals every night to a DDS3 tape and it's disk backups are done with DDS3 tapes.  I cleaned the drive after the errors, but it shows no need be cleaned when it does the incrementals.
>
> I will probably see if the DDS4 drive can search one of the savesets that were created on it on Monday.  Maybe I need to do this kind of stress test to sort things out.
>
> Some of my tests indicate that it's not hitting the parity errors at the same point on the tape.  I tried copying the file twice and it got farther the second time before it had a parity error.
>