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LTO 4 Reported Capacity After Verify -AND- Auto-Use Erased Media

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For clarity, I'll name the two following media set references "Media Set 1 Verify" and "Media Set 2 Backup":


I ran a routine Verify session on my LTO 4 tape media set "Media Set 1 Verify." Prior to this verification, each of the 8 tapes in the media set reported an estimated compressed capacity of 1.6TBs and had used between 850GBs and 990GBs per tape. All good for this LTO 4 media…so far.


After the verification, which automatically picked and read each tape in the set during the process, the reported estimated compressed capacity now shows as 12.8TBs per tape. YIKES! I know Retrospect will always use each tape until full or to failure but I'm REALLY missing the ancient Retrospect 6 feature of being able to assign/override estimated capacity.


Anybody got any ideas on how to get the estimated capacity back to 'normal?' I'm going to rebuild this catalog as 'Fast Catalog Rebuild' is selected for all my tape media sets. I'll report back once complete.


A second issue which presented itself during this media verification:

While "Media Set 1 Verify" was running, so was "Media Set 2 Backup," a different LTO 4 media set in this same T80 Library. Since upgrading to Retrospect 10.5.0, I've had to manually move an erased tape into an available drive when Retrospect showed the "Media Needed" icon and "Waiting for Media" message for both media sets on this Library.


However, all of a sudden "Media Set 2 Backup" started properly picking the next erased media as each tape filled. It continued to do so until "Media Set 1 Verify" was complete. Then it reverted to it's previous 'manual tape insertion' requirement when the current tape was filled.


Note that all tapes in this Library are LTO 4, are either already assigned/named for a given media set or are 'erased' and ready for use by any media set.


I'm checking for drive and library firmware updates now to ensure they are current.


The fun continues.



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Sometime after Retrospect 8, a bug was introduced that caused Retrospect to always display an estimated tape capacity for all members equal to that of the largest tape member in the media set. For example, introducing an LTO-5 tape in a media set where all the previous members were LTO-4 would then cause the displayed total capacity for each of the previous LTO-4 members to double, to match that of the new LTO-5 member. (This behavior did not happen in Retrospect 8, and media sets that haven't been verified or written to since Retro 9 came out still display the expected capacities for each individual member in Retro 10's console.) I suspect what you recently observed is related to this bug, except that the displayed capacity for each individual member is now what should be the estimated capacity for the entire media set. 


Being able to specify an estimated capacity is only one of the many features of Retrospect 6 that many of us wish had not gone away. It will be interesting to see whether a catalog rebuild changes anything.


Your second problem sounds like it too may be a bug in Retro 10.5.

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Thanks for the input, twickland. Happy to report after the rebuild of "Media Set 1 Verify," the estimated capacity for each LTO 4 tape is now 1.6TBs (the compressed theoretical maximum). I also loaded the last tape member in the set and started a backup session. The catalog was properly read and updated and, once the tape was filled, it automatically picked an erased LTO 4 tape and continued the backup. I'll know if automatic erased media selection will continue in about 5 hours. Fingers crossed.


I'll report again if anything of note occurs with this or the "Media Set 2 Backup" media set.


As you note, I expect some more drama when I gradually introduce LTO 5 tapes as we will soon install LTO 5 SAS tape drives in this Library.

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