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oslomike

Rebuild catalog - Problem with one of the tapes

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Hi!

What is the best practice to recover a rebuild when there's a problem with one of the tapes. In this case, the problem came at the very end of the first tape. Retrospect seems to spin as if it's still reading tape, but the tape has stopped and the "replace tape" error lamp is lit on the AIT-2 tape drive. The media set has three sets and the error is on the first tape, again, at the very end of the tape. Can I recover the process and continue with the next tape, or do I have to stop it? If it's possible to recover? Can I add the other tape members to the catalog? I tried once already to stop the process and the catalog seemed to contain the contents of the first tape, minus any snapshots. I did try to repair the catalog but Retrospect asks for the first tape, which of course has a problem. When I put in the first tape again, it did it's thing until the end and then I hit the same problem, "replace tape" lamp comes on. What's best?

thanks

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oslomike,

My gut feeling, from having worked extensively with tapes many years ago on IBM mainframes which didn't yet have disk drives, is that you've got an unreadable end-of-data marker on the first tape Member of the input Backup Set.  The computer operators—a separate profession in those days—used to have a utility program that could write an end-of-tape marker on a tape, but AFAIK we don't have such a program now.  (Some folks may: In 1992 I had backed up my wife's Mac using a Maynard QIC tape drive before I erased her HDD, and the Maynstream backup program—the ancestor of BE—couldn't read the tape to restore it.  I paid DriveSavers US$600 to recover the data from the tape, which they did; it'd now cost around US$2000.)

If you've got the data from that input tape on the output Backup Set, IMHO what you should do is to run another Transfer to the same output Backup Set using only the remaining tape Members of the input Backup Set—starting with the 2nd one.  A way to do that  would be to mark the first tape Member of the input Backup Set as Missing, per the NOTE under "The Members Tab"  starting at the bottom of the left-hand column on page 155 of the Retrospect Mac 6 User's Guide.

 

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49 minutes ago, DavidHertzberg said:

If you've got the data from that input tape on the output Backup Set, IMHO what you should do is to run another Transfer to the same output Backup Set using only the remaining tape Members of the input Backup Set—starting with the 2nd one.  A way to do that  would be to mark the first tape Member of the input Backup Set as Missing, per the NOTE under "The Members Tab"  starting at the bottom of the left-hand column on page 155 of the Retrospect Mac 6 User's Guide.

 

That is what I was thinking after turning off my Mac and going to bed last night. :) 

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Hi Lennart,

 I don't totally understand the what you mean by input and output tapes. In this process I'm speaking about in the orig post, I'm doing a recatalog because the original catalog is lost. So, I don't have the data off the tape yet, just trying to catalog it first.

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11 hours ago, oslomike said:

Hi Lennart,

 I don't totally understand the what you mean by input and output tapes. In this process I'm speaking about in the orig post, I'm doing a recatalog because the original catalog is lost. So, I don't have the data off the tape yet, just trying to catalog it first.

I think David meant source tape and destination tape, respectively (during the copy operation).

MY point was to mark tape 1 as missing during (or before) the recatalog operation.

I'm sorry I didn't make MY point more clear. :) 

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Hi Lennart,

Thanks for the clarification. That makes sense. As far as marking a tape as missing, Retrospect didn't give me that option to continue the process in any way. Can I repair this particular catalog by somehow forcing Retrospect to continue cataloging from the second tape? Seems that when I tried to do a rebuild, it asks for the first tape. I haven't tried repairing starting with the second tape, but I'm curious as to what will happen. 

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oslomike,

Lennart_T is correct; neither your OP or subsequent posts made it clear that you were encountering the problem with the tape during a Rebuild of a Catalog for a AIT Tape Backup Set—I thought it was during a Transfer of that Backup Set to a v6.1 Backup Set.

I also thought you were having this problem using Retrospect Mac 6.1 on your old Mac Pro (2,1).  It wasn't until I read this recent post in one of your other threads that I realized you have connected your Exabyte AIT tape drive to your newer Mac Pro (5,1), so you are encountering these problems running macOS 10.13 High Sierra—as you've said in a recent post in the second of your other threads. 

Naturally the suggestion now occurs to me that you should move your AIT tape drive—and the ATTO SCSI PCI card it's connected to—back to your old Mac Pro (2,1), and try Rebuilding the lost Catalog for that AIT Tape Backup Set on your old machine.   If you can do so including the "bad" first tape (which might only have a bad end-of-data marker when it is read by Retrospect Mac 10.5 under High Sierra; there could have been some limitation in the AIT-drive-handling code), then do a Transfer of all 3 tapes to an LTO Tape Backup Set on the old machine, and copy that complete LTO Tape Backup Set on the new machine—to an LTO Tape Media Set.  If OTOH you still get the error on the "bad" tape, then temporarily postpone copying the "bad" tape by doing what I said in the second paragraph of this up-thread post—with the Transfer of the incomplete AIT Backup Set being to an LTO Tape Backup Set .

After drafting the above paragraphs I went to dinner, and came back to find you had made another post  (up past your Norwegian bedtime, aren't you? 😲).  Frankly I'm getting rather annoyed, oslomike,  with your systematic refusal to clarify in this thread which of your two machines you're talking about. 🤢  I'm here to help you, not to play guessing games.  

Returning to the final sentence of my third long paragraph above—if the AIT tape turns out to be "bad" when read on both machines, you could later do one of two things to accomplish what you're asking Lennart_T how to do in the third sentence of the post directly above this—depending on whether Retrospect will quit when run on your old Mac Pro (2,1).  If it will quit on your Mac Pro(2,1), mark the "bad" tape as Missing from the AIT Tape Backup Set per "The Members Tab" on page 155 of the Retrospect Mac 6 User's Guide and then Rebuild that Backup Set's Catalog with the "good" tapes per "Rebuilding a Catalog"on pages 188–189 of the UG.  Alternatively you could try the "Verifying Media Integrity" operation on pages 190–191 of the Mac 6 UG.  If it won't quit on your Mac Pro(2,1), first quit the Retrospect Engine on your Mac Pro(5,1) or uninstall it—after making a Finder-copy of the files that are in Library->Application Support->Retrospect , then re-install if necessary—followed by a reverse--Finder-copy of the copied  files back into Library->Application Support->Retrospect—and follow the "Verifying a Media Set" procedure on pages 208–210 of the Retrospect Mac 10 User's Guide—doing a Mark Lost for the "bad" tape.  After that follow the "Repairing a Media Set" procedure on pages 210–213 of the Mac 10 UG, clicking the Add Member button for each of the "good" tapes—this may not work unless you click Add Member twice to skip over the "bad" tape.

This 2012 OP of yours raises a new set of questions because it says "I have this old Exabyte Mammoth LT drive", and the Exabyte Mammoth LT has only SCSI connectors.  Yet this very recent post of yours says "I just brought the AIT drive home and it connects via firewire cable".  This later 2012 OP of yours says "Retrospect v6.1 on one partition with Leopard running which will be mostly used for a SONY AIT-2 (firewire interface) and an older Exabyte Mammoth LT drive (SCSI 1 interface via ATTO UL5D card)."  Does that mean the "bad" tape was written on a different AIT tape drive from the drive on your Mac Pro(5,1) which had trouble reading it?  And this CNet page says the interface on the Sony AIT e200-UL is FireWire 400, which means—I also have a Mac Pro (5,1)—that you must be using a FireWire-400-to-800 adapter. Hmmm! 🤔

 

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Hi,

So sorry for all the confusion! I DO appreciate all the help and would hate to stir up any bad feelings. 🙂 I have multiple parallel challenges I'm facing and it's hard for me sometimes to organise it myself. 

In regards to this thread to which I'm replying, I'm having an issue with the first AIT-2 tape of a 3-tape Media Set (Media Set was created using Retrospect 6). The system that was running the rebuild at the time of the "replace media" problem consists of a 5,1 Mac Pro High Sierra. The only tape drive connected is an AIT-2 via firewire. The version of Retrospect is v10.5. (An extra challenge I'm having with this machine is that I cannot get the Retrospect Engine to quit, but I won't get into that now). So after the above mentioned AIT-2 tape encountered some error at the end of the catalog rebuild, I was able to STOP the Retrospect process and it saved the contents of that first tape as a Media Set catalog. I don't find any snapshots but I can search for files and folders. What would be very nice is if I can continue rebuilding that catalog starting from the second tape but keep the contents of the first tape in the catalog.

Here is where it starts to get confusing:

Sitting next to my 5,1 Mac Pro is my 2,1 Mac Pro . It has an ATTO SCSI PCI card connected to it and hanging off the card is an Exabyte tape drive. The Macpro 2,1 is running Retrospect v6.1. There are times when I also connect the AIT-2 drive to this 2,1 Macpro in order to recatalog any AIT tapes that were created with earlier versions of Retrospect (v4 and v5), which the 5,1 Macpro setup won't read (v10.5 reads v6 but nothing earlier). The 2,1 macpro runs v6.1 and it quits just fine.

 

So, back to the original problem of this thread, is there a clear best choice of paths to take to both recatalog and copy the data off the "bad" tape? I understand the different scenarios you mentioned above, I'm just hoping I might get a little guidance as to what to try first, now that you hopefully have a clearer picture. 

 

In regards to older posts about an old Leopard running Mac, I have always used the same drive, or same drive model (I usually keep a spare for when one goes down.). I've never had any problems with reading or writing with the AIT drives and all the data I've retrieved is very well preserved and not much fuss, BUT I have had those drives do some nasty things to the tapes themselves (cut/crunch/twist). Interestingly, my Exabyte tapes are nearly flawless, both mechanically and data integrity wise.

 

I'm really sorry if I'm not as clear as you'd like, I use a lot of time writing these posts, as I I'm sure you do as well, and I apologise if I seem unappreciative. I'm very happy to get help.

Thank you.

 

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oslomike,

Was the Tape Backup Set that contains the "bad" tape originally written with the Exabyte drive?  I'm guessing that this may be so if the Backup Set was created by v4 or v5; the timeline of Retrospect Mac releases at the bottom of this Retrospect History article versus the Wikipedia timeline for the release of AIT-2 seems to show that a Backup Set written up through 1999 couldn't have been written on your AIT-2 drive.

Therefore, if you still have it lying around, I suggest you try re-reading the tapes in that Backup Set using your old Exabyte drive.  I'm not an expert, but differences in mechanical skew between drives can make tapes written on one drive hard to read on another—especially for special characters such as end-of-tape markers. 

Let me tell you a tape story: In 1969 I was working as a programmer at ITT Data Services in Paramus NJ, and my boss asked me to write a program to read "gapless" tapes on the IBM S/360 DOS computer at our satellite Lakehurst office and copy them to ordinary "gapped" tapes.  The "gapless" tapes were being written by the U.S. Navy's Lakehurst Naval Air Station (that's where the Hindenburg dirigible caught fire in 1937),  using a tape drive attached to a radio-telemetry receiver that had no ability to store received data while an inter-block gap was being written.  LNAS could read these "gapless" tapes using a Control Data minicomputer connected to a special tape drive that could somehow "stop in less than 2 inches and navigate backwards to before the stop", but the minicomputer had such a pitifully-small main memory (4K 12-bit words) that the LNAS engineers (testing top-secret aircraft; don't ask 🙄 ) couldn't do any real analysis on it.  The engineers wanted ITT to copy such tapes onto "gapped" ones that could be read by an ordinary tape drive on one of ITT's 512KB OS/360 IBM mainframe computers in Paramus.  I wrote a tricky copy program in S/360 DOS Assembler, and it worked successfully on a test tape.  However it turned out that the LNAS tape drive attached to the radio-telemetry receiver had a skewed read-write head, and the Control Data minicomputer's tape drive read-write head had been skewed to match.  ITT wasn't willing to skew one of its satellite-office IBM tape drives to match, so my program never got used in production.  See an audio expert for an explanation of tape skew.

Edited by DavidHertzberg
Underlines and link in last two sentences of final paragraph, making it clear that the tape drives with skewed read-write heads were _not_ the IBM-standard model that ITT Data Services owned/rented—but were LNAS-owned models from _other_ manufacturers.
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Hi David,

The tapes are definitely AIT-2 tapes and were created is in 2006. I'm almost completely sure that they're v6 Media Sets from my old mac that ran v6 for many years. Right around this time, ca 2006, I had a very unfortunate break-in at work right when I switched computers for the backup machine and the old computer with all of the v4 and v5 catalogs was stolen. Fortunately, I was smart enough to back up "most" of the catalogs on that machine and put them on a newer system backup. I used v6 for a long time, and was kind of late to migrate to v8. I didn't migrate to v8 until about 2010 and that's when I started using LTO. I had a very unfortunate break-in at work right when I switched computers for the backup machine and the old computer with all of the v4 and v5 catalogs was stolen.

Thanks for sharing the story about ITT tape systems, interesting read. 🙂 

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On 1/12/2021 at 6:08 PM, oslomike said:

So, back to the original problem of this thread, is there a clear best choice of paths to take to both recatalog and copy the data off the "bad" tape?

Don't know about best, but what I'd try is:

  1. Rebuild to "tapeset1", starting with the first tape, expecting it to fail at the end of the tape as you've described
  2. Rebuild to "tapeset2", starting with the first tape, expecting it to fail...
  3. Take tape 1 out of the drive!
  4. Repair "tapeset2" and, when it says insert tape 1, mark tape 1 as missing and continue with tapes 2 and 3

You've now got the most data back that you can, albeit in two sets. You could then try and combine them by copying "tapeset1" to a new "diskset1", then "tapeset2" to that "diskset1" -- "diskset1" can then be moved to your newer machine for the conversion.

Your choice as to whether "diskset1" is a File Set or Removable Media Set. You could, perhaps should, copy the two tape sets to two disk sets, convert them to the new format, then combine them -- it'll take longer but might be "safer".

I'd also start to wonder about the chances of me ever needing to go back to data from 10+ years ago and whether it's worth all this extra work! That'd be a struggle between my innate laziness and my OCD, but you may have compliance issues to satisfy.

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Hi Nigel!

Thanks for your insight on what you think is best. It does seem like a good way to go. As you said, It'll probably take longer to get them combined but I think I''ll try that. It's worth a try. You mentioned if it's worth to keep old archives, in my case, the data from 10 year back in time are all multitrack music productions I've worked on, and I'm being surprised all the time by people asking if I can make a new version of a song for a film or something similar. Lucky them I have the archives, though it's not my responsibility. BTW, are there any inexpensive data recovery companies in the UK that specialise in tape recovery? I'm just wondering in case I ever need to get data off a tape that has problems. We have one here in Norway, but it's expensive.

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On 1/15/2021 at 5:15 PM, oslomike said:

and I'm being surprised all the time by people asking if I can make a new version of a song for a film or something similar.

Then, tbh, you need a better system for archiving that data. Like with backups (and I draw a distinction between archive and backup), you should be thinking "3-2-1" -- 3 copies on 2 different media with 1 offsite and, importantly, you should be rotating your archives on to new media more often you have been. High-resilience disk-based storage is relatively cheap and you should use that for your "primary" archive copy. Don't forget to check application versions etc -- you may be near the point where you'll need to re-write old data to new formats...

On 1/15/2021 at 5:15 PM, oslomike said:

BTW, are there any inexpensive data recovery companies in the UK that specialise in tape recovery?

I wouldn't know -- and I'm not sure I'd trust anything over Retrospect for recovering RS's proprietary format (tar tapes would be a different matter). Best to avoid any problems with "3-2-1", media rotation, regular checks that you can retrieve files, and so on.

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oslomike,

I, too,  don't have any knowledge of  "inexpensive data recovery companies in the UK that specialise in tape recovery".  However you could easily get a quotation from this company, by clicking the "Get a quotation" button on the web page and filling in the details—which include an explanation of your problem.  That page sounds as if they might have special software that can copy your one particular AIT tape that has a problem and put a proper end-of-file marker on the copy—regardless of Retrospect's proprietary format, assuming the EOF marker is what you want to know about.

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Does Retrospect have a division of the company that can recover tapes? I'll have to look into that. Thanks for the tip David. 

Regarding the original problem with the one bad tape, I have a little more info I wish to share. Originally,  I was trying to rebuild a catalog with v10.5 of retrospect, which can read v6 media sets. RS 10.5 can indeed read this tape, which is a 6.x media set, but I got that pesky error at the end of the first tape. So, I tried rebuilding that same tape set with the earlier v6.1 Retrospect and alas, it reads the tape just fine, no errors. Go figure. So, in light of that, I managed to get the PCI card to connect my LTO to the v6 machine and I'm just now trying out a transfer/copy of some File sets to a new LTO tape media set. I will then try to rebuild that LTO tape with RS v10.5 and see if the new catalog also contains all of the snapshots. I'll let you know how it goes

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oslomike,

Based on announcements made at the time of its 2019 acquisition by StorCentric, Retrospect Inc. had about 20 employees—with most working from home.  It has never in its 30-year history had any hardware-related capability.  In fact before Dantz Development Corp. was acquired by EMC in 2004, Dantz used to get driver source code from the manufacturers of various kinds of tape drives—and hire contractors to rewrite that code so it would interface with Retrospect Mac and Windows.  That's how Retrospect at the time of its acquisition by EMC had cornered 90% of the market for Mac backup software, and more Windows users than Mac users.  (EMC end-of-lifed Retrospect Mac after disk-destination Time Machine was released.)

Sometimes the manufacturer's driver code would have bugs, and sometimes the contractors would introduce bugs—which is probably why Retrospect Mac 6.1 can't use the hardware compression capability of my HP DAT72 tape drive.  A lot of Retrospect's terrible reputation among IT old-timers, which they've expressed to me in my 4-year-old Retrospect thread on the Ars Technica Mac forum, results from the defects of its tape drivers—note that the linked-to post says another app's AIT driver worked better.   It sounds as if there might be a bug in the Retrospect Mac 10.5 AIT driver code, although it might use an AIT driver provided by Apple in later versions of Mac OS X.  Your idea of copying your AIT Tape Backup Set to an LTO tape using Retrospect Mac 6.1 is excellent, because LTO is an industry-standard tape format with less flexibility for drive manufacturers.

 

Edited by DavidHertzberg
Add link to Ars Technica post In second paragraph; the post recounts AIT bugs in Retrospect 6.1. Add to first paragraph remark that EMC EOL'ed Retrospect Mac.

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David,

Thanks for the history lesson! I find it interesting. I suspect there's some bugs several places. In fact, after just now creating a new LTO media set using RS 6.1 (transferred a file set to a tape media set: LTO-5), and then rebuilding that same media set (reading the LTO-5 tape) using RS 10.5, alas there's no snapshots in the new 10.5 catalog. I'm almost completely sure that the snapshots are they're there on the LTO tape because RS 6.1 shows me all of them when attempting a restore. Is it possible that the snapshots didn't get written to the LTO tape by RS 6.1? Some setting I might have overlooked? I hope I didn't explain that too poorly.  Well, I'm starting to give up on the idea of consolidating everything to LTO tapes running on one machine. Just doesn't seem doable. It is a big plus to have the data on LTO tapes, even if it's still running on v6.1; it consolidates so many 8mm tapes and it's so much faster. I truly thought this was going to end up different. Maybe it's pilot error, could very well be. I'll keep trying. Thanks for everyone's help, it's much appreciated.

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After rebuilding the v6.1 media set using RS 10.5, the catalog shows that there's 335 backups in the media set. Is there a trick to accessing them? They don't show up on Backups Tab nor can I "retrieve" any. Looks as if there's 335 backups somewhere. 

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