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Is there a problem with Retro when it hits 1TB of backup?

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We aren't there yet, but a couple of people in my college have commented that Retro 6.1 seems to start barfing when catalog sets go over 1TB:


1) (User backs up to 2TB HD Raid set): "Retrospect stops at 1TB and asks for another disk even though my drive is almost 2TB."


2) "Retrospect just always seemed to have problems once the backup set got over

1TB. We'd have problems with the catalogue constantly corrupting and since

our finished set for 2-3 months was about 3TB we've gotten to the point of

"write only" backups. Restoring, when possible, takes around a week. We

managed by splitting our backup sets into smaller chunks, but that ends up

with more scripts we need to manage." (this user also backs up to disk -- not tape)



These are long-time Retrospect users who now feel they need to look for something else to manage such large data sets.


Is there some known issue with problems once the sets get over 1TB?


If not, is there something they may be doing wrong (both are admins who I trust to normally do the right thing with their systems, so I take their commentary fairly seriously...)

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User backs up to 2TB HD Raid set



Although nowhere in your post do you describe the Type of Backup Set being used, it appears that your user has told Retrospect for treat hard drives as removable devices (Special->Preferences->Media Handling), and that you are using Removable Backup Sets with RAID arrays as Members.


All I can suggest is that Removable Backup Sets were originally designed for floppy, Zip, MO, etc, devices. The ability to use fixed platter hard drives as Removable Devices was added to Retrospect recently (I think 5.1?). This is different from the Disk Backup Set introduced for the Windows product, which was designed specifically for this purpose.


Perhaps the old code in Retrospect just can't handle Removable Backup Sets this large. Perhaps your users would have more success with File Backup Sets, if their Destination volumes can be made large enough to store the data.



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Correct -- "removable devices" -- I do the same thing here backing up my XServe, but it's only a 640M RAID unit, so I'm not going to hit this problem.


But I'd thought of moving my other tape systems that backup my client machines to RAID HD units, but if there's a 1TB limit per storage set, that'll be a problem...

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I know it's difficult to be the go-between for user reports, but #2 above has me confused as to exactly what's happening.


We managed by splitting our backup sets into smaller chunks, but that ends up with more scripts we need to manage.


Seems to imply File Backup Sets; with Removable Backup Sets the user would need not only more scripts to manage, but would need a dedicated hard drive (or array of drives) for each of these scripts. I'd think such a requirement would get noted in his complaint, no?


One of the major changes from 5.x to 6.x was the breaking of the TB barrier; that's why there is no backwards (writing) compatibility to older Backup Sets.


- Are #1 and #2 the same user?

- Can you confirm exactly how things are configured for each user?

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#1 and #2 are different users.


#2 actually backed up to multiple drives (hence getting around the 1TB/removable device limit that seems to be there):


I now see this in the documentation on-line:


Using hard drives as removable disks: Retrospect's Media Handling preference formerly known as “Use FireWire/USB hard drives as removable disks” has been changed to “Use hard drives as removable disks”. This new preference allows Retrospect to use Xserve RAID devices, as well as hard drives connected to the backup server via USB, FireWire, Fibre Channel, ATA, or SCSI, as destinations for removable disk backup sets. Previously these drives (with the exception of FireWire and USB) could only be used as the destination for file backup sets. Since removable disk backup sets support asynchronous data transfer (and file backup sets do not), this preference provides improved data transfer speeds. To access this preference choose Special>Preferences>Media Handling. When this preference is selected, all local volumes (except the startup disk) will appear in Retrospect’s Storage Devices window (Configure>Volumes). These volumes will also appear in the media request window for removable disk backup sets, and they can be selected as the backup set destination.


WARNING: Retrospect requires exclusive use of any volume selected for use in a removable disk backup set and it erases the volume entirely before using it the first time.


There are some limitations to consider when using hard drives as removable disk backup set members. Retrospect will only write 1 TB of data to any single member. After 1 TB it will ask for a new member and span to that member, regardless of how much available space remains on the previous member. If you have a large capacity hard drive that you want to use as part of a removable disk backup set, partition the drive into segments of 1 TB or less for optimal use with Retrospect.



That explains it...

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