teacher24_70 Posted January 20, 2008 Report Share Posted January 20, 2008 Can Retrospect be used to backup one external hard drive to another? Link to comment Share on other sites More sharing options...
rhwalker Posted January 20, 2008 Report Share Posted January 20, 2008 Are you talking about "backup" or duplicate (cloning / copying)? They are very different things. Russ Link to comment Share on other sites More sharing options...
teacher24_70 Posted January 22, 2008 Author Report Share Posted January 22, 2008 Backup. I just recently moved my iTunes library over to a new WD Passport hard-drive, but I want to be able to run incremental backups of this hard-drive when I do my routine incremental backups of my internal. The internal drive would be backing up to one external drive, while the new Passport would be backing up to a different external drive. Link to comment Share on other sites More sharing options...
CallMeDave Posted January 22, 2008 Report Share Posted January 22, 2008 A File Backup Set consists of two files ("BackupSetFoo" and "BackupSetFoo.cat") that you can store on any volume, as long as that volume has enough free space to hold the files, which will grow as you perform incremental backups. So although your configuration descriptions remain unclear, the short answer is probably "yes." Link to comment Share on other sites More sharing options...
rhwalker Posted January 22, 2008 Report Share Posted January 22, 2008 Then the answer is yes, it can back up from one external drive to another. They are just seen as volumes, doesn't matter whether they are internal or external. Note, however: (1) there are some external drives that can't stand the continuous-duty pounding that they get from Retrospect, and they overheat and give errors. I think the MyBook is in this category; don't know about your drives, but this is not a Retrospect problem; it's a hardware design problem with the drive. (2) You don't say what your hardware configuration is, and how your external drives are connected. SCSI? FireWire? NAS? Some drive cases have bad Firewire chipsets and give problems. Don't know about your drives. (3) there will be the issue of space - your backup sets will grow, and the Mac version of Retrospect does not have grooming (ability to delete older files in the backup set, keeping only a certain number of recent snapshots), so you will periodically have to reset the backup set and start over (or get another drive). Russ Link to comment Share on other sites More sharing options...
teacher24_70 Posted February 3, 2008 Author Report Share Posted February 3, 2008 Here's a little more information and one more question. I have a 750 gig MyBook, daisy chained to a 120 gig Rocstor, daisy chained to a DVD burner--all daisy chained and attached via Firewire. It would be the 750 gig MyBook that would be the destination for the backup of my new WD Passport (250 Gig) iTunes library. However, the WD Passport is connected to the laptop via USB. I already back up my laptop HD to the Rocstor, so I'm used to doing Recycle Backups. I have a 12 inch G4 Powerbook--1.33 Ghz, 80 gig drive running Tiger 10.4.11. My one remaining question is will there be an issue with having the 750 Gig destination drive hooked up through Firewire and the WD Passport hooked up through USB? Link to comment Share on other sites More sharing options...
CallMeDave Posted February 3, 2008 Report Share Posted February 3, 2008 Quote: will there be an issue with having the 750 Gig destination drive hooked up through Firewire and the WD Passport hooked up through USB? They physical bus technologies have inherent limitations, and Retrospect will work within those limitations. USB works better one-way-at-a-time then it does reading-from/writing-to at the same time. So if data on the USB is simply being read by Retrospect while being written to a File Backup Set stored on a FireWire hard drive, it should work just fine. You would probably have problems if you tried to write data to the USB at the same time. Dave Link to comment Share on other sites More sharing options...
teacher24_70 Posted February 5, 2008 Author Report Share Posted February 5, 2008 Wow! 13-14 hours later, it finally backed up my 116.17 gig WD Passport drive. I didn't think that it would take so long, but I guess having to route from one USB drive, into the Powerbook, and then back out the Firewire drive slowed things down. Question. Is it normal for a 116 gig drive to create a 144.63 gig backup set? If this were the 2nd or 3rd incremental backup to the set, that would make sense, but this was the very first! 28 1/2 gig seems to be a mighty big difference! 2nd question. I created a script for the backup. When someone else created my first backup using Retrospect, they created a run script that I could place in the dock. I thought that I would be able to do that with this one, but I must have set something up wrong. How can I go back and create a run script that can be placed outside of the program? Link to comment Share on other sites More sharing options...
rhwalker Posted February 5, 2008 Report Share Posted February 5, 2008 Quote: Question. Is it normal for a 116 gig drive to create a 144.63 gig backup set? If this were the 2nd or 3rd incremental backup to the set, that would make sense, but this was the very first! 28 1/2 gig seems to be a mighty big difference! Reviewing the lengthy thread, it appears that you have a "file" backup set. In that case, the answer might be yes because, in addition to the 116 Gig of data, there is all the catalog information that indexes each file into the backup set. It's a database, not just data. I only use tape backup, so it's hard for me to compare with your results, but our tape catalogs (uncompressed) are on the order of 1 GB per 100 GB of data. So, yes, your number sounds a little high, but I haven't used "file" backup sets, so I don't know whether their catalog structure is less compact than that for "disk" or "tape" backup sets and, of course, the size of the catalog will depend on the number of files. We have some big data files, you might have many, many little ones. Russ Link to comment Share on other sites More sharing options...
teacher24_70 Posted February 6, 2008 Author Report Share Posted February 6, 2008 I guess maybe it took a little longer because it's default was to have "verification" and "data compression" on. I'm assuming that since it's default, it's an okay option to have on. However, I would think that having data compression on would have caused the backup set to be smaller, not larger! By the way, I figured how to create the Run document. I just hadn't gone far enough into Retrospect--I had thought that by asking it to run, it was cause it to run again instead of giving me the option to finally create the Run document. Link to comment Share on other sites More sharing options...
rhwalker Posted February 6, 2008 Report Share Posted February 6, 2008 As a comment, we do tape backups, and the tape drive does hardware compression of the data. However, we store the catalog (which is separate for tape backups) as uncompressed. Makes browsing of a backup set much faster, and cuts off an hour or more from the end of the backup (because catalog compression is not needed). Once we archive a backup set and stop writing to it, we compress the catalog and leave it compressed, because our catalogs become rather large, and the archived backup sets are rarely accessed. Russ Link to comment Share on other sites More sharing options...
PaulMikeC Posted February 13, 2008 Report Share Posted February 13, 2008 Just throwing out another possibility... From my own experience, when software-compression is enabled, and the built-in '~Compression Filter' Selector isn't already configured to ignore certain file-types, Retrospect can often end up trying to recompress already-compressed data (e.g., '.m4a', '.m4p' or 'm4v' media files from the iTunes Store). At best, this could consume a great deal of extra time for little if any size-reduction, and at worst it could also even slightly increase the size of the backup. If this fits your situation, you could just edit that built-in '~Compression Filter' Selector (first saving a backup copy of your '/Library/Preferences/Retrospect/Retro.Config (m.n)' file just in case), to add the additional file-types and/or filename-extensions that you wish to exclude from recompression. Good luck, --Paul Link to comment Share on other sites More sharing options...
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