larth Posted December 8, 2003 Report Share Posted December 8, 2003 Here's the sitch. When I go to do a selective restore, I frequently find erased tapes in the middle of my backup set. For example, let's say, in a set of 4 tapes, tape number 2 is reported as Erased. I can still restore files from the other three tapes...but if it's on tape 2, it's lost. According to the Knowledgebase, when a tape is reported as Erased "it is the tape drive which is relaying this message to your computer". However, a tech from Seagate claims that "in order for the tape drive to return a status of erased the drive must [...] see a header that physically states that the tape is blank and contains no information. Assuming both statements are true, then tape 2 has a header explicitly describing the tape as "erased", and the drive is relaying that info to Retrospect. This begs the question: How does tape 2 end up with an "erased" header when Retrospect claims that a bunch of my data was backed up on there? No errors are ever reported during backup. I clean the tape drive regularly per the manufacturer's instructions. It's the only device on the SCSI chain, and is properly terminated. The problem even existed on a previous tape drive with entirely different SCSI cables and card. I need theories! Anybody? --larth Link to comment Share on other sites More sharing options...
natew Posted December 12, 2003 Report Share Posted December 12, 2003 Hi, Things like this can happen when read and write heads are out of allignment but that sounds unlikely in your case. Any chance you can try one of the erased tapes in another drive to see if it reads properly? My understanding is that if there is no Data found on the header of the tape then it is reported as erased. If there is data that is not Retrospect data it shows as Content unrecognized. Does this happen with new backups as well? Nate Link to comment Share on other sites More sharing options...
larth Posted December 29, 2003 Author Report Share Posted December 29, 2003 natew said: >>>Any chance you can try one of the erased tapes in another drive to see if it reads properly? I have only one DDS-4 drive, unfortunately. I'd likely have two of them if I wasn't so turned off by the unreliability I've experienced. >>>My understanding is that if there is no Data found on the header of the tape then it is reported as erased. If there is data that is not Retrospect data it shows as Content unrecognized. Hmm... It's not as if I really know for certain, but what you say contradicts the guy at Seagate. He insists that the drive only reports a tape as erased if an "erased" message was written to the headers. It'd be nice to know for sure which theory is correct. >>>Does this happen with new backups as well? The backups appear to go off without a hitch. I can't say for sure if the tapes in question are good for a while, or if they're corrupt right off the bat. I haven't kept that close a tab on things, though I could certainly start. --larth Link to comment Share on other sites More sharing options...
natew Posted December 30, 2003 Report Share Posted December 30, 2003 Hi Make sure you have verification on for the backup. That will tell you if the tape was readable at the time of backup. I suspect the heads are out of alignment. If that is the case the tapes that show as erased may be readable in another drive. It is also likely that the backups you are making now will not be readable elsewhere. Nate Link to comment Share on other sites More sharing options...
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