bpieber Posted October 30, 2009 Report Share Posted October 30, 2009 (edited) I have moved to a new Mac. When I tried a restore from a DVD backup set recently Retrospect 6.1.230 failed to read one of the segments. The DVD looked like an empty DVD to the new Mac. However, on my old Mac the restore worked. Thank god I still had it! I tried all the DVDs on the new computer and found out that 10 out of 79 are not readable from the new Mac. That is very frustrating! What should I do now? I don't want to keep the old Mac forever. Is it somehow possible to copy individual DVDs from a backup set. I tried that using Toast but that did not work due to a read error. Any help is greatly appreciated. Edited October 30, 2009 by Guest Quote Link to comment Share on other sites More sharing options...
Lennart_T Posted October 30, 2009 Report Share Posted October 30, 2009 You can use the "Transfer" option in Retrospect to create a new backup set. Quote Link to comment Share on other sites More sharing options...
rhwalker Posted October 30, 2009 Report Share Posted October 30, 2009 Is it somehow possible to copy individual DVDs from a backup set. I tried that using Toast but that did not work due to a read error. Did you try Toast on the old computer? Did you try Disk Utility on the old computer to make a disk image (sparseimage) and then burn that to a new DVD? Another thing to try would be to put the old computer into Target Disk Mode, attach it to the new computer using Firewire, use Retrospect on the new computer to "Transfer" the backup set from the DVDs as read by the old computer's DVD drive in Firewire mode. Russ Quote Link to comment Share on other sites More sharing options...
bpieber Posted October 30, 2009 Author Report Share Posted October 30, 2009 Yes, I tried to copy one of the DVDs with Toast 8.0.5 on the old computer. It fails almost instantly saying the disc has a read error. However, that DVDs which work on the new computer behave the same. Therefore I guess it has to do with the format Retrospect uses called retrospectcd. I also tried to copy the DVD with Disk Utility on the old computer. That fails with an in-/output error. As the failing DVDs look like empty DVDs to the new Mac it looks as if the disc was not finalized correctly. However, if I look at Toast's Disc-Info working and failing DVDs look the same. I searched the Internet but so far I did not find anything that might help. Thanks for your support! Quote Link to comment Share on other sites More sharing options...
bpieber Posted October 30, 2009 Author Report Share Posted October 30, 2009 Yes, I thought about that possibility as well. I fear that it will run for days in my case. And I would probably have to do it twice - once to a hard disc and then again to DVDs on the new computer. I still hope to find a way so that I only need to transfer the 10 failing DVDs and not all 79 DVDs of my backup set. Thanks for your help! Quote Link to comment Share on other sites More sharing options...
rhwalker Posted October 30, 2009 Report Share Posted October 30, 2009 No, you should only have to do the transfer once. Put one of the Macs (probably best to do this with the old one so that Retrospect runs on the new Mac with better hardware) into Target Disk Mode, attach it with a Firewire cable to the other Mac running Retrospect, use Retrospect to Transfer the backup set from the DVD set in the old drive to a new DVD set in the new drive. My concern is that all of the 79 DVDs may be slowly failing; I would do the transfer to another set using the new drive, which probably has a clean lens, etc. I would look at this as an opportunity to make a full backup set that is readable on the new Mac and that will be readable for some time to come. Good time waster for a Saturday. Russ Quote Link to comment Share on other sites More sharing options...
bpieber Posted October 30, 2009 Author Report Share Posted October 30, 2009 I booted my old computer into Target Disk Mode. I see my old computer's hard disks mounted on my new computer. When I insert a DVD into my old computer I get an error message "Medium inserted: The inserted medium cannot be read by this computer" with two buttons "Eject" or "Ignore". If I click "Ignore" the medium stays in but no volume is mounted on the new computer. This happens with good and bad DVDs. When I open Retrospect on the new computer I cannot access the old backup set. In the devices list only the local DVD drive is shown. Now I am stuck. How can I access the old DVD backup set as a source for the transfer? Thanks for your support! Bernhard Quote Link to comment Share on other sites More sharing options...
rhwalker Posted October 31, 2009 Report Share Posted October 31, 2009 (edited) That's surprising because I believe that I have been able to put an iMac into TDM and see its DVD drive. I thought it worked that way on all. In fact, I know I did it with our xServe. See, for example, pages 31 and 57: Mac OS X Server 10.6 - Getting Started Looks like you are stuck with the double transfer. An option, depending on what hardware skills you have available, would be to pull the DVD drive from the old Mac and attach it to the new Mac. Perhaps you have an external hard drive case around that would do the trick. Russ Edited October 31, 2009 by Guest Quote Link to comment Share on other sites More sharing options...
bpieber Posted November 5, 2009 Author Report Share Posted November 5, 2009 That's surprising because I believe that I have been able to put an iMac into TDM and see its DVD drive. I thought it worked that way on all. In fact, I know I did it with our xServe. See, for example, pages 31 and 57: Mac OS X Server 10.6 - Getting Started I gave it another try. I put my old computer in TDM and inserted a mountable DVD. In this case I can see it from the new computer. Retrospect sees it as well, albeit as removable medium not as a DVD: Mountable DVD However, if I insert a Retrospect DVD it looks like that: Retrospect DVD So even the drive is gone in Retrospect. So it looks like a double transfer is needed. An option, depending on what hardware skills you have available, would be to pull the DVD drive from the old Mac and attach it to the new Mac. Perhaps you have an external hard drive case around that would do the trick. I must admit that I am slightly worried that if I mess with the drive it might cease to work in the old computer as well. That would be a catastrophe. Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 5, 2009 Report Share Posted November 5, 2009 My German language skills are non-existent (some say that my English language skills are as well). Could you post a screen shot of Retrospect's Configure > Get Status screen? I believe that it's the "Geratestatus" button on your Configure screen shot. It's possible that the device is being ignored. You might also have to adjust the settings for Special > Preferences > Media Handling (handling of removable disks) Russ Quote Link to comment Share on other sites More sharing options...
bpieber Posted November 5, 2009 Author Report Share Posted November 5, 2009 (edited) Could you post a screen shot of Retrospect'sConfigure > Get Status screen? I believe that it's the "Geratestatus" button on your Configure screen shot. Here you go: Drive Status Only the local DVD drive is there. That does not change even if I press "Search Again". It's possible that the device is being ignored. Yes, it looks like this is the case. You might also have to adjust the settings forSpecial > Preferences > Media Handling (handling of removable disks) I guess you mean this - this time in English ;-) : Media Handling Preferences I only checked "Eject media". I don't see how any of these might make a difference, though. My guess is that since a TDM linked dvd drive looks like a removable media drive Retrospects proprietary DVD format is not recognised. Anyway, thanks for helping me! Edited November 5, 2009 by Guest Quote Link to comment Share on other sites More sharing options...
bpieber Posted November 5, 2009 Author Report Share Posted November 5, 2009 (edited) I wonder if it is really a proprietary format. If not, it might be possible to find a program that can copy it. I tried Carbon Copy Cloner and even Mac the Ripper. Neither worked. :-( Edited November 5, 2009 by Guest Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 5, 2009 Report Share Posted November 5, 2009 It's not so much that it is a proprietary format (yes, it is), but that Retrospect uses "packet writing" vs. "track at once" commands. See, for example: KB article discussing packet writing vs. track at once Russ Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 5, 2009 Report Share Posted November 5, 2009 My guess is that since a TDM linked dvd drive looks like a removable media drive Retrospects proprietary DVD format is not recognised. I really don't think that is it. What happens if you check the removable media box (the bottom checkbox)? I wish I could be of more help here - we only use Retrospect with tapes. Russ Quote Link to comment Share on other sites More sharing options...
bpieber Posted November 7, 2009 Author Report Share Posted November 7, 2009 Thanks for your support, Russ! It's also a big help to know someone cares! I just finished a transfer of my 79 DVD backup set into a file backup set on an external hard disk on my old computer. (It ran for 23 hours total.) There were read errors of 4 files on 2 DVDs. (Interestingly, these 2 DVDs are not part of the 10 DVDs which do not work on my new computer.) I found out which 4 files had the read errors by comparing the content of the sessions of the two backup sets. It turned out that all 4 files were also on other DVDs of the source backup set. I created a selector for those 4 files and were able to restore them from the new backup set. I was relieved. Though I am worried that there has been no verification after the transfer. How can I be sure that all the files were transferred correctly? Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 7, 2009 Report Share Posted November 7, 2009 Though I am worried that there has been no verification after the transfer. How can I be sure that all the files were transferred correctly? This is why Retrospect Windows and Retrospect 8 for Mac (and many other backup programs) use MD5 polynomials as a part of the backup, saving away (off of the backup medium) the calculated MD5 checksum for each file so that the MD5 values can be compared to validate the files. There's really no way except to try to validate each of the files. I guess you could do a restore from each of the backup sets, then write a little script to recurse the filesystem tree and compare the files, etc. It all depends on how much faith you have in your backup software. Retrospect 6 is very mature. If it reports errors, I believe them. If it doesn't report errors, I feel confident. The only data integrity issue of which I am aware with Retrospect 6, on the platforms for which it is supported (i.e., pre Snow Leopard), is that some metadata is not always preserved correctly. But the file data itself is backed up and restored. Russ Quote Link to comment Share on other sites More sharing options...
bpieber Posted November 7, 2009 Author Report Share Posted November 7, 2009 This is why Retrospect Windows and Retrospect 8 for Mac (and many other backup programs) use MD5 polynomials as a part of the backup, saving away (off of the backup medium) the calculated MD5 checksum for each file so that the MD5 values can be compared to validate the files. Yes, I already bought the upgrade to Retrospect 8. However, I don't want to use it until it reads or imports 6.1 backup sets. I hope that happens soon. It all depends on how much faith you have in your backup software. Retrospect 6 is very mature. If it reports errors, I believe them. If it doesn't report errors, I feel confident. I must admit that my confidence in Retrospect is very low currently due to that incident. Both DVD drives are supported by Retrospect, still I cannot restore 12% of my archive on my new Mac! Thank god I had not yet sold my old one! But the file data itself is backed up and restored. Well, in my case the restore does not work. If that DVDs cannot be made to work somehow on my new Mac, how can I ever trust DVD backup sets again? Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 7, 2009 Report Share Posted November 7, 2009 Perhaps I should have been more specific. I only use Retrospect for tape backup and restore. I have little experience with DVD backup / restore. However, note this NIST report: Stability Comparison of Recordable Optical Discs Russ Quote Link to comment Share on other sites More sharing options...
bpieber Posted November 7, 2009 Author Report Share Posted November 7, 2009 Hi Russ, Sorry for my rambling in the last post. You have been tremendously helpful so far. That report about optical media looks very interesting. I try to buy good media. In my case all the DVDs are from Sony. I started with DVD-Rs and switched to DVD+R when I saw EMC recommending it over DVD-R. I do not doubt optical media as such. My feeling is not that the discs itself have gotten bad but it has to do with the way it was burned. Mainly because all the discs work without problem whatsoever on the old Mac. And from my 79 DVDs, number 6 to 9, 11 to 15 and 77 don't work in the new computer. And 77 looks a little different - the new Mac shows it as Unknown instead of Deleted. Anyway, as soon as Retrospect 8 will be able to read 6.1 backup sets I will ask EMC tech support about it. Thanks again! Cheers, Bernhard Quote Link to comment Share on other sites More sharing options...
rhwalker Posted November 7, 2009 Report Share Posted November 7, 2009 I think that the bottom line recommendation is to buy good media and store it in a cool dark place. Anyway, as soon as Retrospect 8 will be able to read 6.1 backup sets I will ask EMC tech support about it. We have tape backup sets back to Retrospect 2.0 (1993) that we need to retrieve, and you can't do unattended server backups without scripting (need to coordinate shutting down services, checkpointing, restarting services, etc.). I think that the reliability needs to improve, too. Right now, it seems that the users are doing all of the testing and QA. Russ Quote Link to comment Share on other sites More sharing options...
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